| Antrim County (ACB) | Bellaire | MI | Walter A Duncan Field Illinois Valley Regional to Antrim County |
| Lenawee County (ADG) | Adrian | MI | Walter A Duncan Field Illinois Valley Regional to Lenawee County |
| Albert Lea Municipal (AEL) | Albert Lea | MN | Walter A Duncan Field Illinois Valley Regional to Albert Lea Municipal |
| Amery Municipal (AHH) | Amery | WI | Walter A Duncan Field Illinois Valley Regional to Amery Municipal |
| Anderson Municipal-Darlington Field (AID) | Anderson | IN | Walter A Duncan Field Illinois Valley Regional to Anderson Municipal-Darlington Field |
| Atlantic Municipal (AIO) | Atlantic | IA | Walter A Duncan Field Illinois Valley Regional to Atlantic Municipal |
| Lee C Fine Memorial (AIZ) | KAISER/LAKE OZARK | MO | Walter A Duncan Field Illinois Valley Regional to Lee C Fine Memorial |
| Akron Fulton International (AKC) | Akron | OH | Walter A Duncan Field Illinois Valley Regional to Akron Fulton International |
| St Louis Regional (ALN) | Alton | IL | Walter A Duncan Field Illinois Valley Regional to St Louis Regional |
| Waterloo Regional (ALO) | Waterloo | IA | Walter A Duncan Field Illinois Valley Regional to Waterloo Regional |
| Gratiot Community (AMN) | Alma | MI | Walter A Duncan Field Illinois Valley Regional to Gratiot Community |
| Ames Municipal (AMW) | Ames | IA | Walter A Duncan Field Illinois Valley Regional to Ames Municipal |
| Tri-State Steuben County (ANQ) | Angola | IN | Walter A Duncan Field Illinois Valley Regional to Tri-State Steuben County |
| Lima Allen County (AOH) | Lima | OH | Walter A Duncan Field Illinois Valley Regional to Lima Allen County |
| Alpena County Regional (APN) | Alpena | MI | Walter A Duncan Field Illinois Valley Regional to Alpena County Regional |
| Ann Arbor Municipal (ARB) | Ann Arbor | MI | Walter A Duncan Field Illinois Valley Regional to Ann Arbor Municipal |
| Walnut Ridge Regional (ARG) | Walnut Ridge | AR | Walter A Duncan Field Illinois Valley Regional to Walnut Ridge Regional |
| Lakeland/Noble F. Lee Memorial Field (ARV) | Minocqua | WI | Walter A Duncan Field Illinois Valley Regional to Lakeland/Noble F. Lee Memorial Field |
| John F Kennedy Memorial (ASX) | Ashland | WI | Walter A Duncan Field Illinois Valley Regional to John F Kennedy Memorial |
| Gordon K Bush Ohio University (ATO) | Athens/Albany | OH | Walter A Duncan Field Illinois Valley Regional to Gordon K Bush Ohio University |
| Appleton International (ATW) | Appleton | WI | Walter A Duncan Field Illinois Valley Regional to Appleton International |
| Austin Municipal (AUM) | Austin | MN | Walter A Duncan Field Illinois Valley Regional to Austin Municipal |
| Wausau Downtown (AUW) | Wausau | WI | Walter A Duncan Field Illinois Valley Regional to Wausau Downtown |
| Chicago/Aurora Municipal (AUZ) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Chicago/Aurora Municipal |
| Algona Municipal (AXG) | Algona | IA | Walter A Duncan Field Illinois Valley Regional to Algona Municipal |
| Auglaize County Neil Armstrong (AXV) | Wapakoneta | OH | Walter A Duncan Field Illinois Valley Regional to Auglaize County Neil Armstrong |
| Kalamazoo/Battle Creek International (AZO) | Kalamazoo | MI | Walter A Duncan Field Illinois Valley Regional to Kalamazoo/Battle Creek International |
| Southwest Michigan Regional (BEH) | Benton Harbor | MI | Walter A Duncan Field Illinois Valley Regional to Southwest Michigan Regional |
| Virgil I Grissom Municipal (BFR) | Bedford | IN | Walter A Duncan Field Illinois Valley Regional to Virgil I Grissom Municipal |
| Wayne County (BJJ) | Wooster | OH | Walter A Duncan Field Illinois Valley Regional to Wayne County |
| Branson (BKG) | Branson | MO | Walter A Duncan Field Illinois Valley Regional to Branson |
| Burke Lakefront (BKL) | Cleveland | OH | Walter A Duncan Field Illinois Valley Regional to Burke Lakefront |
| MidAmerica St Louis Scott AFB (BLV) | Belleville | IL | Walter A Duncan Field Illinois Valley Regional to MidAmerica St Louis Scott AFB |
| Monroe County (BMG) | Bloomington | IN | Walter A Duncan Field Illinois Valley Regional to Monroe County |
| Central Illinois Regional at Bloomington Normal (BMI) | Bloomington | IL | Walter A Duncan Field Illinois Valley Regional to Central Illinois Regional at Bloomington Normal |
| Nashville International (BNA) | Nashville | TN | Walter A Duncan Field Illinois Valley Regional to Nashville International |
| Boone Municipal (BNW) | Boone | IA | Walter A Duncan Field Illinois Valley Regional to Boone Municipal |
| Southeast Iowa Regional (BRL) | Burlington | IA | Walter A Duncan Field Illinois Valley Regional to Southeast Iowa Regional |
| Samuels Field (BRY) | Bardstown | KY | Walter A Duncan Field Illinois Valley Regional to Samuels Field |
| Battle Creek Executive (BTL) | Battle Creek | MI | Walter A Duncan Field Illinois Valley Regional to Battle Creek Executive |
| Butler Memorial (BUM) | Butler | MO | Walter A Duncan Field Illinois Valley Regional to Butler Memorial |
| Bowling Green Warren County Regional (BWG) | Bowling Green | KY | Walter A Duncan Field Illinois Valley Regional to Bowling Green Warren County Regional |
| Arkansas International (BYH) | Blytheville | AR | Walter A Duncan Field Illinois Valley Regional to Arkansas International |
| Wexford County (CAD) | Cadillac | MI | Walter A Duncan Field Illinois Valley Regional to Wexford County |
| Council Bluffs Municipal (CBF) | Council Bluffs | IA | Walter A Duncan Field Illinois Valley Regional to Council Bluffs Municipal |
| Northeast Iowa Regional (CCY) | Charles City | IA | Walter A Duncan Field Illinois Valley Regional to Northeast Iowa Regional |
| Mettel Field (CEV) | Connersville | IN | Walter A Duncan Field Illinois Valley Regional to Mettel Field |
| Kyle-Oakley Field (CEY) | Murray | KY | Walter A Duncan Field Illinois Valley Regional to Kyle-Oakley Field |
| Cuyahoga County (CGF) | Cleveland | OH | Walter A Duncan Field Illinois Valley Regional to Cuyahoga County |
| Cape Girardeau Regional (CGI) | Cape Girardeau | MO | Walter A Duncan Field Illinois Valley Regional to Cape Girardeau Regional |
| The Eastern Iowa (CID) | Cedar Rapids | IA | Walter A Duncan Field Illinois Valley Regional to The Eastern Iowa |
| Arthur N Neu (CIN) | Carroll | IA | Walter A Duncan Field Illinois Valley Regional to Arthur N Neu |
| Cairo Regional (CIR) | Cairo | IL | Walter A Duncan Field Illinois Valley Regional to Cairo Regional |
| Outlaw Field (CKV) | Clarksville | TN | Walter A Duncan Field Illinois Valley Regional to Outlaw Field |
| Cleveland/Hopkins International (CLE) | Cleveland | OH | Walter A Duncan Field Illinois Valley Regional to Cleveland/Hopkins International |
| Clintonville Municipal (CLI) | Clintonville | WI | Walter A Duncan Field Illinois Valley Regional to Clintonville Municipal |
| Columbus Municipal (CLU) | Columbus | IN | Walter A Duncan Field Illinois Valley Regional to Columbus Municipal |
| John Glenn International (CMH) | Columbus | OH | Walter A Duncan Field Illinois Valley Regional to John Glenn International |
| University of Illinois-Willard (CMI) | Champaign/Urbana | IL | Walter A Duncan Field Illinois Valley Regional to University of Illinois-Willard |
| Sparta/Fort Mccoy (CMY) | Sparta | WI | Walter A Duncan Field Illinois Valley Regional to Sparta/Fort Mccoy |
| Columbia Regional (COU) | Columbia | MO | Walter A Duncan Field Illinois Valley Regional to Columbia Regional |
| St Louis Downtown (CPS) | Cahokia/St Louis | IL | Walter A Duncan Field Illinois Valley Regional to St Louis Downtown |
| Creston Municipal (CSQ) | Creston | IA | Walter A Duncan Field Illinois Valley Regional to Creston Municipal |
| Canton Municipal (CTK) | Canton | SD | Walter A Duncan Field Illinois Valley Regional to Canton Municipal |
| Cincinnati Northern Kentucky International (CVG) | Cincinnati | OH | Walter A Duncan Field Illinois Valley Regional to Cincinnati Northern Kentucky International |
| Central Wisconsin (CWA) | Mosinee | WI | Walter A Duncan Field Illinois Valley Regional to Central Wisconsin |
| Clinton Municipal (CWI) | Clinton | IA | Walter A Duncan Field Illinois Valley Regional to Clinton Municipal |
| Dayton International James M Cox (DAY) | Dayton | OH | Walter A Duncan Field Illinois Valley Regional to Dayton International James M Cox |
| Dubuque Regional (DBQ) | Dubuque | IA | Walter A Duncan Field Illinois Valley Regional to Dubuque Regional |
| Decatur (DEC) | Decatur | IL | Walter A Duncan Field Illinois Valley Regional to Decatur |
| Decorah Municipal (DEH) | Decorah | IA | Walter A Duncan Field Illinois Valley Regional to Decorah Municipal |
| Coleman A Young Municipal (DET) | Detroit | MI | Walter A Duncan Field Illinois Valley Regional to Coleman A Young Municipal |
| Defiance Memorial (DFI) | Defiance | OH | Walter A Duncan Field Illinois Valley Regional to Defiance Memorial |
| Sedalia Regional (DMO) | Sedalia | MO | Walter A Duncan Field Illinois Valley Regional to Sedalia Regional |
| Denison Municipal (DNS) | Denison | IA | Walter A Duncan Field Illinois Valley Regional to Denison Municipal |
| Vermilion Regional (DNV) | Danville | IL | Walter A Duncan Field Illinois Valley Regional to Vermilion Regional |
| Dupage (DPA) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Dupage |
| Des Moines International (DSM) | Des Moines | IA | Walter A Duncan Field Illinois Valley Regional to Des Moines International |
| Detroit Metro Wayne County (DTW) | Detroit | MI | Walter A Duncan Field Illinois Valley Regional to Detroit Metro Wayne County |
| Davenport Municipal (DVN) | Davenport | IA | Walter A Duncan Field Illinois Valley Regional to Davenport Municipal |
| Chippewa Valley Regional (EAU) | Eau Claire | WI | Walter A Duncan Field Illinois Valley Regional to Chippewa Valley Regional |
| Webster City Municipal (EBS) | Webster City | IA | Walter A Duncan Field Illinois Valley Regional to Webster City Municipal |
| Iosco County (ECA) | East Tawas | MI | Walter A Duncan Field Illinois Valley Regional to Iosco County |
| Jefferson Municipal (EFW) | Jefferson | IA | Walter A Duncan Field Illinois Valley Regional to Jefferson Municipal |
| Eagle River Union (EGV) | Eagle River | WI | Walter A Duncan Field Illinois Valley Regional to Eagle River Union |
| Elkhart Municipal (EKI) | Elkhart | IN | Walter A Duncan Field Illinois Valley Regional to Elkhart Municipal |
| Addington Field (EKX) | Elizabethtown | KY | Walter A Duncan Field Illinois Valley Regional to Addington Field |
| Centralia Municipal (ENL) | Centralia | IL | Walter A Duncan Field Illinois Valley Regional to Centralia Municipal |
| Kenosha Regional (ENW) | Kenosha | WI | Walter A Duncan Field Illinois Valley Regional to Kenosha Regional |
| Keokuk Municipal (EOK) | Keokuk | IA | Walter A Duncan Field Illinois Valley Regional to Keokuk Municipal |
| Delta County (ESC) | Escanaba | MI | Walter A Duncan Field Illinois Valley Regional to Delta County |
| Estherville Municipal (EST) | Estherville | IA | Walter A Duncan Field Illinois Valley Regional to Estherville Municipal |
| West Bend Municipal (ETB) | West Bend | WI | Walter A Duncan Field Illinois Valley Regional to West Bend Municipal |
| Evansville Regional (EVV) | Evansville | IN | Walter A Duncan Field Illinois Valley Regional to Evansville Regional |
| Farmington Regional (FAM) | Farmington | MO | Walter A Duncan Field Illinois Valley Regional to Farmington Regional |
| Faribault Municipal (FBL) | Faribault | MN | Walter A Duncan Field Illinois Valley Regional to Faribault Municipal |
| Flying Cloud (FCM) | Minneapolis | MN | Walter A Duncan Field Illinois Valley Regional to Flying Cloud |
| Findlay (FDY) | Findlay | OH | Walter A Duncan Field Illinois Valley Regional to Findlay |
| Albertus (FEP) | Freeport | IL | Walter A Duncan Field Illinois Valley Regional to Albertus |
| Fremont Municipal (FET) | Fremont | NE | Walter A Duncan Field Illinois Valley Regional to Fremont Municipal |
| Fairfield Municipal (FFL) | Fairfield | IA | Walter A Duncan Field Illinois Valley Regional to Fairfield Municipal |
| Capital City (FFT) | Frankfort | KY | Walter A Duncan Field Illinois Valley Regional to Capital City |
| Fond Du Lac County (FLD) | Fond Du Lac | WI | Walter A Duncan Field Illinois Valley Regional to Fond Du Lac County |
| Marion County Regional (FLP) | Flippin | AR | Walter A Duncan Field Illinois Valley Regional to Marion County Regional |
| Sherman Army Airfield (FLV) | Fort Leavenworth | KS | Walter A Duncan Field Illinois Valley Regional to Sherman Army Airfield |
| Fort Madison Municipal (FMS) | Fort Madison | IA | Walter A Duncan Field Illinois Valley Regional to Fort Madison Municipal |
| Bishop International (FNT) | Flint | MI | Walter A Duncan Field Illinois Valley Regional to Bishop International |
| Fort Dodge Regional (FOD) | Fort Dodge | IA | Walter A Duncan Field Illinois Valley Regional to Fort Dodge Regional |
| Topeka Regional (FOE) | Topeka | KS | Walter A Duncan Field Illinois Valley Regional to Topeka Regional |
| French Lick Municipal (FRH) | French Lick | IN | Walter A Duncan Field Illinois Valley Regional to French Lick Municipal |
| Fairmont Municipal (FRM) | Fairmont | MN | Walter A Duncan Field Illinois Valley Regional to Fairmont Municipal |
| Fort Scott Municipal (FSK) | Fort Scott | KS | Walter A Duncan Field Illinois Valley Regional to Fort Scott Municipal |
| Fort Wayne International (FWA) | Fort Wayne | IN | Walter A Duncan Field Illinois Valley Regional to Fort Wayne International |
| Branson West Municipal - Emerson Field (FWB) | Branson West | MO | Walter A Duncan Field Illinois Valley Regional to Branson West Municipal - Emerson Field |
| Forest City Municipal (FXY) | Forest City | IA | Walter A Duncan Field Illinois Valley Regional to Forest City Municipal |
| Galesburg Municipal (GBG) | Galesburg | IL | Walter A Duncan Field Illinois Valley Regional to Galesburg Municipal |
| Gladwin Zettel Memorial (GDW) | Gladwin | MI | Walter A Duncan Field Illinois Valley Regional to Gladwin Zettel Memorial |
| Centerville Municipal (GHM) | Centerville | TN | Walter A Duncan Field Illinois Valley Regional to Centerville Municipal |
| Gaylord Regional (GLR) | Gaylord | MI | Walter A Duncan Field Illinois Valley Regional to Gaylord Regional |
| Glasgow Municipal (GLW) | Glasgow | KY | Walter A Duncan Field Illinois Valley Regional to Glasgow Municipal |
| Galion Municipal (GQQ) | Galion | OH | Walter A Duncan Field Illinois Valley Regional to Galion Municipal |
| Austin Straubel International (GRB) | Green Bay | WI | Walter A Duncan Field Illinois Valley Regional to Austin Straubel International |
| Greenville (GRE) | Greenville | IL | Walter A Duncan Field Illinois Valley Regional to Greenville |
| Gerald R Ford International (GRR) | Grand Rapids | MI | Walter A Duncan Field Illinois Valley Regional to Gerald R Ford International |
| Goshen Municipal (GSH) | Goshen | IN | Walter A Duncan Field Illinois Valley Regional to Goshen Municipal |
| Grantsburg Muni (GTG) | Grantsburg | WI | Walter A Duncan Field Illinois Valley Regional to Grantsburg Muni |
| Grissom Aeroplex/Arb (GUS) | Peru | IN | Walter A Duncan Field Illinois Valley Regional to Grissom Aeroplex/Arb |
| Gary/Chicago International (GYY) | GARY | IN | Walter A Duncan Field Illinois Valley Regional to Gary/Chicago International |
| Three Rivers Municipal Dr Haines (HAI) | Three Rivers | MI | Walter A Duncan Field Illinois Valley Regional to Three Rivers Municipal Dr Haines |
| Butler County Regional-Hogan Field (HAO) | Hamilton | OH | Walter A Duncan Field Illinois Valley Regional to Butler County Regional-Hogan Field |
| Blytheville Municipal (HKA) | Blytheville | AR | Walter A Duncan Field Illinois Valley Regional to Blytheville Municipal |
| Park Township (HLM) | Holland | MI | Walter A Duncan Field Illinois Valley Regional to Park Township |
| Huntingburg (HNB) | Huntingburg | IN | Walter A Duncan Field Illinois Valley Regional to Huntingburg |
| Hampton Municipal (HPT) | Hampton | IA | Walter A Duncan Field Illinois Valley Regional to Hampton Municipal |
| Harrisburg-Raleigh (HSB) | Harrisburg | IL | Walter A Duncan Field Illinois Valley Regional to Harrisburg-Raleigh |
| Roscommon County - Blodgett Memorial (HTL) | Houghton Lake | MI | Walter A Duncan Field Illinois Valley Regional to Roscommon County - Blodgett Memorial |
| Tri-State Milton J Ferguson Field (HTS) | Huntington | WV | Walter A Duncan Field Illinois Valley Regional to Tri-State Milton J Ferguson Field |
| Humboldt Municipal (HUD) | Humboldt | IA | Walter A Duncan Field Illinois Valley Regional to Humboldt Municipal |
| Terre Haute Regional (HUF) | Terre Haute | IN | Walter A Duncan Field Illinois Valley Regional to Terre Haute Regional |
| Sawyer County (HYR) | Hayward | WI | Walter A Duncan Field Illinois Valley Regional to Sawyer County |
| Schenck Field (ICL) | Clarinda | IA | Walter A Duncan Field Illinois Valley Regional to Schenck Field |
| Ida Grove Municipal (IDG) | Ida Grove | IA | Walter A Duncan Field Illinois Valley Regional to Ida Grove Municipal |
| Iowa Falls Municipal (IFA) | Iowa Falls | IA | Walter A Duncan Field Illinois Valley Regional to Iowa Falls Municipal |
| Jacksonville Municipal (IJX) | Jacksonville | IL | Walter A Duncan Field Illinois Valley Regional to Jacksonville Municipal |
| Greater Kankakee (IKK) | Kankakee | IL | Walter A Duncan Field Illinois Valley Regional to Greater Kankakee |
| Willmar Municipal/John L Rice Field (ILL) | Willmar | MN | Walter A Duncan Field Illinois Valley Regional to Willmar Municipal/John L Rice Field |
| Wilmington Airpark (ILN) | Wilmington | OH | Walter A Duncan Field Illinois Valley Regional to Wilmington Airpark |
| Ford (IMT) | Iron Mountain | MI | Walter A Duncan Field Illinois Valley Regional to Ford |
| Indianapolis International (IND) | Indianapolis | IN | Walter A Duncan Field Illinois Valley Regional to Indianapolis International |
| Iowa City Municipal (IOW) | Iowa City | IA | Walter A Duncan Field Illinois Valley Regional to Iowa City Municipal |
| Kirksville Regional (IRK) | Kirksville | MO | Walter A Duncan Field Illinois Valley Regional to Kirksville Regional |
| Kirsch Municipal (IRS) | Sturgis | MI | Walter A Duncan Field Illinois Valley Regional to Kirsch Municipal |
| Schoolcraft County (ISQ) | Manistique | MI | Walter A Duncan Field Illinois Valley Regional to Schoolcraft County |
| Alexander Field South Wood County (ISW) | Wisconsin Rapids | WI | Walter A Duncan Field Illinois Valley Regional to Alexander Field South Wood County |
| Gogebic-Iron County (IWD) | Ironwood | MI | Walter A Duncan Field Illinois Valley Regional to Gogebic-Iron County |
| Jonesboro Municipal (JBR) | Jonesboro | AR | Walter A Duncan Field Illinois Valley Regional to Jonesboro Municipal |
| New Century Aircenter (JCI) | Olathe | KS | Walter A Duncan Field Illinois Valley Regional to New Century Aircenter |
| Jefferson City Memorial (JEF) | Jefferson City | MO | Walter A Duncan Field Illinois Valley Regional to Jefferson City Memorial |
| Joliet Regional Airport (JOT) | Joliet | IL | Walter A Duncan Field Illinois Valley Regional to Joliet Regional Airport |
| Souther Wisconsin Regional (JVL) | Janesville | WI | Walter A Duncan Field Illinois Valley Regional to Souther Wisconsin Regional |
| Jackson County/Reynolds Field (JXN) | Jackson | MI | Walter A Duncan Field Illinois Valley Regional to Jackson County/Reynolds Field |
| Kentland Municipal (KKT) | Kentland | IN | Walter A Duncan Field Illinois Valley Regional to Kentland Municipal |
| Kennett Memorial (KNT) | Kennett | MO | Walter A Duncan Field Illinois Valley Regional to Kennett Memorial |
| Purdue University (LAF) | Lafayette | IN | Walter A Duncan Field Illinois Valley Regional to Purdue University |
| Capital Region International (LAN) | Lansing | MI | Walter A Duncan Field Illinois Valley Regional to Capital Region International |
| Rickenbacker International (LCK) | Columbus | OH | Walter A Duncan Field Illinois Valley Regional to Rickenbacker International |
| Mason County (LDM) | Ludington | MI | Walter A Duncan Field Illinois Valley Regional to Mason County |
| Blue Grass (LEX) | Lexington | KY | Walter A Duncan Field Illinois Valley Regional to Blue Grass |
| Leamington (LM2) | Leamington | ON | Walter A Duncan Field Illinois Valley Regional to Leamington |
| Lincoln Municipal (LNK) | Lincoln | NE | Walter A Duncan Field Illinois Valley Regional to Lincoln Municipal |
| Tri-County Regional (LNR) | Lone Rock | WI | Walter A Duncan Field Illinois Valley Regional to Tri-County Regional |
| Lewis University Chicago Romeoville (LOT) | Chicago/Romeoville | IL | Walter A Duncan Field Illinois Valley Regional to Lewis University Chicago Romeoville |
| Bowman Field (LOU) | Louisville | KY | Walter A Duncan Field Illinois Valley Regional to Bowman Field |
| London Corbin Magee Field (LOZ) | London | KY | Walter A Duncan Field Illinois Valley Regional to London Corbin Magee Field |
| La Porte Municipal (LPO) | La Porte | IN | Walter A Duncan Field Illinois Valley Regional to La Porte Municipal |
| Le Mars Municipal (LRJ) | Le Mars | IA | Walter A Duncan Field Illinois Valley Regional to Le Mars Municipal |
| La Crosse Regional (LSE) | La Crosse | WI | Walter A Duncan Field Illinois Valley Regional to La Crosse Regional |
| Cincinnati Municipal Lunken (LUK) | Cincinnati | OH | Walter A Duncan Field Illinois Valley Regional to Cincinnati Municipal Lunken |
| Lawrence Municipal (LWC) | Lawrence | KS | Walter A Duncan Field Illinois Valley Regional to Lawrence Municipal |
| Lawrenceville-Vincennes International (LWV) | Lawrenceville | IL | Walter A Duncan Field Illinois Valley Regional to Lawrenceville-Vincennes International |
| Quentin Aanenson Field (LYV) | Luverne | MN | Walter A Duncan Field Illinois Valley Regional to Quentin Aanenson Field |
| Malden Regional (MAW) | Malden | MO | Walter A Duncan Field Illinois Valley Regional to Malden Regional |
| Manistee County-Blacker (MBL) | Manistee | MI | Walter A Duncan Field Illinois Valley Regional to Manistee County-Blacker |
| Mbs International (MBS) | Saginaw | MI | Walter A Duncan Field Illinois Valley Regional to Mbs International |
| Omar N Bradley (MBY) | Moberly | MO | Walter A Duncan Field Illinois Valley Regional to Omar N Bradley |
| Mackinac Island (MCD) | Mackinac Island | MI | Walter A Duncan Field Illinois Valley Regional to Mackinac Island |
| Kansas City International (MCI) | Kansas City | MO | Walter A Duncan Field Illinois Valley Regional to Kansas City International |
| Mason City Municipal (MCW) | Mason City | IA | Walter A Duncan Field Illinois Valley Regional to Mason City Municipal |
| Taylor County (MDF) | Medford | WI | Walter A Duncan Field Illinois Valley Regional to Taylor County |
| Southern Illinois (MDH) | Carbondale/Murphysboro | IL | Walter A Duncan Field Illinois Valley Regional to Southern Illinois |
| Madison Municipal (MDN) | Madison | IN | Walter A Duncan Field Illinois Valley Regional to Madison Municipal |
| Chicago Midway International (MDW) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Chicago Midway International |
| Mansfield Lahm Regional (MFD) | Mansfield | OH | Walter A Duncan Field Illinois Valley Regional to Mansfield Lahm Regional |
| Marshfield Municipal (MFI) | Marshfield | WI | Walter A Duncan Field Illinois Valley Regional to Marshfield Municipal |
| Michigan City Municipal-Phillips Field (MGC) | Michigan City | IN | Walter A Duncan Field Illinois Valley Regional to Michigan City Municipal-Phillips Field |
| Dayton-Wright Brothers (MGY) | Dayton | OH | Walter A Duncan Field Illinois Valley Regional to Dayton-Wright Brothers |
| Marshall Memorial Municipal (MHL) | Marshall | MO | Walter A Duncan Field Illinois Valley Regional to Marshall Memorial Municipal |
| Crystal (MIC) | Minneapolis | MN | Walter A Duncan Field Illinois Valley Regional to Crystal |
| Delaware County Regional (MIE) | Muncie | IN | Walter A Duncan Field Illinois Valley Regional to Delaware County Regional |
| Omaha Millard (MIQ) | Omaha | NE | Walter A Duncan Field Illinois Valley Regional to Omaha Millard |
| Marshalltown Municipal (MIW) | Marshalltown | IA | Walter A Duncan Field Illinois Valley Regional to Marshalltown Municipal |
| Jackson Municipal (MJQ) | Jackson | MN | Walter A Duncan Field Illinois Valley Regional to Jackson Municipal |
| Charles B Wheeler Downtown (MKC) | Kansas City | MO | Walter A Duncan Field Illinois Valley Regional to Charles B Wheeler Downtown |
| Milwaukee Mitchell International (MKE) | Milwaukee | WI | Walter A Duncan Field Illinois Valley Regional to Milwaukee Mitchell International |
| Muskegon County (MKG) | Muskegon | MI | Walter A Duncan Field Illinois Valley Regional to Muskegon County |
| Mckellar Sipes Regional (MKL) | Jackson | TN | Walter A Duncan Field Illinois Valley Regional to Mckellar Sipes Regional |
| Mankato Regional (MKT) | Mankato | MN | Walter A Duncan Field Illinois Valley Regional to Mankato Regional |
| Quad City International (MLI) | Moline | IL | Walter A Duncan Field Illinois Valley Regional to Quad City International |
| Southwest Minnesota Regional Marshall/Ryan Field (MML) | Marshall | MN | Walter A Duncan Field Illinois Valley Regional to Southwest Minnesota Regional Marshall/Ryan Field |
| Menominee-Marinette Twin County (MNM) | Menominee | MI | Walter A Duncan Field Illinois Valley Regional to Menominee-Marinette Twin County |
| Marion Municipal (MNN) | Marion | OH | Walter A Duncan Field Illinois Valley Regional to Marion Municipal |
| Mount Pleasant Municipal (MOP) | Mount Pleasant | MI | Walter A Duncan Field Illinois Valley Regional to Mount Pleasant Municipal |
| Mount Pleasant Municipal (MPZ) | Mount Pleasant | IA | Walter A Duncan Field Illinois Valley Regional to Mount Pleasant Municipal |
| Macomb Municipal (MQB) | Macomb | IL | Walter A Duncan Field Illinois Valley Regional to Macomb Municipal |
| Sawyer International (MQT) | Marquette | MI | Walter A Duncan Field Illinois Valley Regional to Sawyer International |
| Smyrna (MQY) | Smyrna | TN | Walter A Duncan Field Illinois Valley Regional to Smyrna |
| Truax Field/Dane County Regional (MSN) | Madison | WI | Walter A Duncan Field Illinois Valley Regional to Truax Field/Dane County Regional |
| Minneapolis St Paul International/Wold-Chamberlain (MSP) | Minneapolis | MN | Walter A Duncan Field Illinois Valley Regional to Minneapolis St Paul International/Wold-Chamberlain |
| Coles County Memorial (MTO) | Mattoon/Charleston | IL | Walter A Duncan Field Illinois Valley Regional to Coles County Memorial |
| Manitowoc County (MTW) | Manitowoc | WI | Walter A Duncan Field Illinois Valley Regional to Manitowoc County |
| Muscatine Municipal (MUT) | Muscatine | IA | Walter A Duncan Field Illinois Valley Regional to Muscatine Municipal |
| Mount Vernon (MVN) | Mount Vernon | IL | Walter A Duncan Field Illinois Valley Regional to Mount Vernon |
| Williamson County Rgnl (MWA) | Marion | IL | Walter A Duncan Field Illinois Valley Regional to Williamson County Rgnl |
| Lawrence J Timmerman (MWC) | Milwaukee | WI | Walter A Duncan Field Illinois Valley Regional to Lawrence J Timmerman |
| Windom Municipal (MWM) | Windom | MN | Walter A Duncan Field Illinois Valley Regional to Windom Municipal |
| Middletown Regional - Hook Field (MWO) | Middletown | OH | Walter A Duncan Field Illinois Valley Regional to Middletown Regional - Hook Field |
| Manila Municipal (MXA) | Manila | AR | Walter A Duncan Field Illinois Valley Regional to Manila Municipal |
| Monticello Regional (MXO) | Monticello | IA | Walter A Duncan Field Illinois Valley Regional to Monticello Regional |
| Marion Municipal (MZZ) | Marion | IN | Walter A Duncan Field Illinois Valley Regional to Marion Municipal |
| Jerry Tyler Memorial (NLE) | Niles | MI | Walter A Duncan Field Illinois Valley Regional to Jerry Tyler Memorial |
| Slayton Municipal (NSL) | Slayton | MN | Walter A Duncan Field Illinois Valley Regional to Slayton Municipal |
| Nevada Municipal (NVD) | Nevada | MO | Walter A Duncan Field Illinois Valley Regional to Nevada Municipal |
| L O Simenstad Municipal (OEO) | Osceola | WI | Walter A Duncan Field Illinois Valley Regional to L O Simenstad Municipal |
| Johnson County Executive (OJC) | Olathe | KS | Walter A Duncan Field Illinois Valley Regional to Johnson County Executive |
| Kokomo Municipal (OKK) | Kokomo | IN | Walter A Duncan Field Illinois Valley Regional to Kokomo Municipal |
| Olney-Noble (OLY) | Olney-Noble | IL | Walter A Duncan Field Illinois Valley Regional to Olney-Noble |
| Eppley Airfield (OMA) | Omaha | NE | Walter A Duncan Field Illinois Valley Regional to Eppley Airfield |
| Winona Municipal-Max Conrad Field (ONA) | Winona | MN | Walter A Duncan Field Illinois Valley Regional to Winona Municipal-Max Conrad Field |
| Oskaloosa Municipal (OOA) | Oskaloosa | IA | Walter A Duncan Field Illinois Valley Regional to Oskaloosa Municipal |
| Chicago O'hare International (ORD) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Chicago O'hare International |
| Grand Glaize Osage Beach (OSB) | Osage Beach | MO | Walter A Duncan Field Illinois Valley Regional to Grand Glaize Osage Beach |
| Oscoda-Wurtsmith (OSC) | Oscoda | MI | Walter A Duncan Field Illinois Valley Regional to Oscoda-Wurtsmith |
| Wittman Regional (OSH) | Oshkosh | WI | Walter A Duncan Field Illinois Valley Regional to Wittman Regional |
| Ohio State University (OSU) | Columbus | OH | Walter A Duncan Field Illinois Valley Regional to Ohio State University |
| Worthington Municipal (OTG) | Worthington | MN | Walter A Duncan Field Illinois Valley Regional to Worthington Municipal |
| Ottumwa Regional (OTM) | Ottumwa | IA | Walter A Duncan Field Illinois Valley Regional to Ottumwa Regional |
| Owatonna Degner Regional (OWA) | Owatonna | MN | Walter A Duncan Field Illinois Valley Regional to Owatonna Degner Regional |
| Owensboro-Daviess County Regional (OWB) | Owensboro | KY | Walter A Duncan Field Illinois Valley Regional to Owensboro-Daviess County Regional |
| Miami University (OXD) | Oxford | OH | Walter A Duncan Field Illinois Valley Regional to Miami University |
| Barkley Regional (PAH) | Paducah | KY | Walter A Duncan Field Illinois Valley Regional to Barkley Regional |
| Prairie Du Chien Municipal (PCD) | Prairie Duchien | WI | Walter A Duncan Field Illinois Valley Regional to Prairie Du Chien Municipal |
| Paragould/Kirk Field (PGR) | Paragould | AR | Walter A Duncan Field Illinois Valley Regional to Paragould/Kirk Field |
| St Clair County International (PHN) | Port Huron | MI | Walter A Duncan Field Illinois Valley Regional to St Clair County International |
| Henry County (PHT) | Paris | TN | Walter A Duncan Field Illinois Valley Regional to Henry County |
| Gen Wayne A Downing Peoria International (PIA) | Peoria | IL | Walter A Duncan Field Illinois Valley Regional to Gen Wayne A Downing Peoria International |
| Park Falls Municipal (PKF) | Park Falls | WI | Walter A Duncan Field Illinois Valley Regional to Park Falls Municipal |
| M. Graham Clark Downtown (PLK) | Point Lookout | MO | Walter A Duncan Field Illinois Valley Regional to M. Graham Clark Downtown |
| Pellston Regional of Emmet County (PLN) | Pellston | MI | Walter A Duncan Field Illinois Valley Regional to Pellston Regional of Emmet County |
| Plymouth Municipal (PLY) | Plymouth | IN | Walter A Duncan Field Illinois Valley Regional to Plymouth Municipal |
| Greater Portsmouth Regional (PMH) | Portsmouth | OH | Walter A Duncan Field Illinois Valley Regional to Greater Portsmouth Regional |
| Poplar Bluff Municipal (POF) | Poplar Bluff | MO | Walter A Duncan Field Illinois Valley Regional to Poplar Bluff Municipal |
| Pocahontas Municipal (POH) | Pocahontas | IA | Walter A Duncan Field Illinois Valley Regional to Pocahontas Municipal |
| Perry Municipal (PRO) | Perry | IA | Walter A Duncan Field Illinois Valley Regional to Perry Municipal |
| Prentice Municipal (PRW) | Prentice | WI | Walter A Duncan Field Illinois Valley Regional to Prentice Municipal |
| Oakland County International (PTK) | Pontiac | MI | Walter A Duncan Field Illinois Valley Regional to Oakland County International |
| Atkinson Municipal (PTS) | Pittsburg | KS | Walter A Duncan Field Illinois Valley Regional to Atkinson Municipal |
| Chicago Executive (PWK) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Chicago Executive |
| Batten International (RAC) | Racine | WI | Walter A Duncan Field Illinois Valley Regional to Batten International |
| Fulton County (RCR) | Rochester | IN | Walter A Duncan Field Illinois Valley Regional to Fulton County |
| Nartron Field (RCT) | Reed City | MI | Walter A Duncan Field Illinois Valley Regional to Nartron Field |
| Chicago/Rockford International (RFD) | Rockford | IL | Walter A Duncan Field Illinois Valley Regional to Chicago/Rockford International |
| Rhinelander Oneida County (RHI) | Rhinelander | WI | Walter A Duncan Field Illinois Valley Regional to Rhinelander Oneida County |
| Richmond Municipal (RID) | Richmond | IN | Walter A Duncan Field Illinois Valley Regional to Richmond Municipal |
| Rice Lake Regional - Carl's Field (RIE) | Rice Lake | WI | Walter A Duncan Field Illinois Valley Regional to Rice Lake Regional - Carl's Field |
| Rolla Downtown (RLA) | Rolla | MO | Walter A Duncan Field Illinois Valley Regional to Rolla Downtown |
| New Richmond Regional (RNH) | New Richmond | WI | Walter A Duncan Field Illinois Valley Regional to New Richmond Regional |
| Jasper County (RNZ) | Rensselaer | IN | Walter A Duncan Field Illinois Valley Regional to Jasper County |
| Merrill Municipal (RRL) | Merrill | WI | Walter A Duncan Field Illinois Valley Regional to Merrill Municipal |
| Rochester International (RST) | Rochester | MN | Walter A Duncan Field Illinois Valley Regional to Rochester International |
| Spirit Lake Municipal (RTL) | Spirit Lake | IA | Walter A Duncan Field Illinois Valley Regional to Spirit Lake Municipal |
| Redwood Falls Municipal (RWF) | Redwood Falls | MN | Walter A Duncan Field Illinois Valley Regional to Redwood Falls Municipal |
| Sparta Community - Hunter Field (SAR) | Sparta | IL | Walter A Duncan Field Illinois Valley Regional to Sparta Community - Hunter Field |
| Sheboygan County Memorial (SBM) | Sheboygan | WI | Walter A Duncan Field Illinois Valley Regional to Sheboygan County Memorial |
| South Bend International (SBN) | South Bend | IN | Walter A Duncan Field Illinois Valley Regional to South Bend International |
| Scribner State (SCB) | Scribner | NE | Walter A Duncan Field Illinois Valley Regional to Scribner State |
| Louisville International/Standiford Field (SDF) | Louisville | KY | Walter A Duncan Field Illinois Valley Regional to Louisville International/Standiford Field |
| Freeman Municipal (SER) | Seymour | IN | Walter A Duncan Field Illinois Valley Regional to Freeman Municipal |
| Springfield/Branson National (SGF) | Springfield | MO | Walter A Duncan Field Illinois Valley Regional to Springfield/Branson National |
| Springfield/Beckley Municipal (SGH) | Springfield | OH | Walter A Duncan Field Illinois Valley Regional to Springfield/Beckley Municipal |
| Sikeston Memorial Municipal (SIK) | Sikeston | MO | Walter A Duncan Field Illinois Valley Regional to Sikeston Memorial Municipal |
| Sullivan County (SIV) | Sullivan | IN | Walter A Duncan Field Illinois Valley Regional to Sullivan County |
| Storm Lake Municipal (SLB) | Storm Lake | IA | Walter A Duncan Field Illinois Valley Regional to Storm Lake Municipal |
| Salem-Leckrone (SLO) | Salem | IL | Walter A Duncan Field Illinois Valley Regional to Salem-Leckrone |
| Smith Field (SMD) | Fort Wayne | IN | Walter A Duncan Field Illinois Valley Regional to Smith Field |
| Lake Cumberland Regional (SME) | Somerset | KY | Walter A Duncan Field Illinois Valley Regional to Lake Cumberland Regional |
| Abraham Lincoln Capital (SPI) | Springfield | IL | Walter A Duncan Field Illinois Valley Regional to Abraham Lincoln Capital |
| Spencer Municipal/Northwest Iowa Regional (SPW) | Spencer | IA | Walter A Duncan Field Illinois Valley Regional to Spencer Municipal/Northwest Iowa Regional |
| St Cloud Regional (STC) | St Cloud Regional | MN | Walter A Duncan Field Illinois Valley Regional to St Cloud Regional |
| Stevens Point Municipal (STE) | Stevens Point | WI | Walter A Duncan Field Illinois Valley Regional to Stevens Point Municipal |
| Rosecrans Memorial (STJ) | St Joseph | MO | Walter A Duncan Field Illinois Valley Regional to Rosecrans Memorial |
| Lambert St Louis International (STL) | St Louis | MO | Walter A Duncan Field Illinois Valley Regional to Lambert St Louis International |
| St Paul Downtown Holman Field (STP) | St Paul | MN | Walter A Duncan Field Illinois Valley Regional to St Paul Downtown Holman Field |
| Door County Cherryland (SUE) | Sturgeon Bay | WI | Walter A Duncan Field Illinois Valley Regional to Door County Cherryland |
| Spirit of St Louis (SUS) | St Louis | MO | Walter A Duncan Field Illinois Valley Regional to Spirit of St Louis |
| Richard I Bong Memorial (SUW) | Superior | WI | Walter A Duncan Field Illinois Valley Regional to Richard I Bong Memorial |
| Sioux Gateway/Col Bud Day Field (SUX) | Sioux City | IA | Walter A Duncan Field Illinois Valley Regional to Sioux Gateway/Col Bud Day Field |
| Waynesville St Robert Regional/Forney Field (TBN) | Fort Leonard Wood | MO | Walter A Duncan Field Illinois Valley Regional to Waynesville St Robert Regional/Forney Field |
| Toledo Executive (TDZ) | Toledo | OH | Walter A Duncan Field Illinois Valley Regional to Toledo Executive |
| Newton Municipal (TNU) | Newton | IA | Walter A Duncan Field Illinois Valley Regional to Newton Municipal |
| Toledo Express (TOL) | Toledo | OH | Walter A Duncan Field Illinois Valley Regional to Toledo Express |
| Philip Billard Municipal (TOP) | Topeka | KS | Walter A Duncan Field Illinois Valley Regional to Philip Billard Municipal |
| Trenton Municipal (TRX) | Trenton | MO | Walter A Duncan Field Illinois Valley Regional to Trenton Municipal |
| Cherry Capital (TVC) | Traverse City | MI | Walter A Duncan Field Illinois Valley Regional to Cherry Capital |
| Tuscola Area (TZC) | Caro | MI | Walter A Duncan Field Illinois Valley Regional to Tuscola Area |
| Everett-Stewart Regional (UCY) | Union City | TN | Walter A Duncan Field Illinois Valley Regional to Everett-Stewart Regional |
| Waukesha County (UES) | Waukesha | WI | Walter A Duncan Field Illinois Valley Regional to Waukesha County |
| Chicago/Waukegan Regional (UGN) | Chicago | IL | Walter A Duncan Field Illinois Valley Regional to Chicago/Waukegan Regional |
| Baldwin Field/Quincy Regional (UIN) | Quincy | IL | Walter A Duncan Field Illinois Valley Regional to Baldwin Field/Quincy Regional |
| Waukon Municipal Airport (UKN) | Waukon | IA | Walter A Duncan Field Illinois Valley Regional to Waukon Municipal Airport |
| New Ulm Municipal (ULM) | New Ulm | MN | Walter A Duncan Field Illinois Valley Regional to New Ulm Municipal |
| Dodge County (UNU) | Juneau | WI | Walter A Duncan Field Illinois Valley Regional to Dodge County |
| Rolla National (VIH) | Rolla/Vichy | MO | Walter A Duncan Field Illinois Valley Regional to Rolla National |
| Vandalia Municipal (VLA) | Vandalia | IL | Walter A Duncan Field Illinois Valley Regional to Vandalia Municipal |
| Porter County Regional (VPZ) | Valparaiso | IN | Walter A Duncan Field Illinois Valley Regional to Porter County Regional |
| Roy Otten Memorial Airfield (VRS) | Versailles | MO | Walter A Duncan Field Illinois Valley Regional to Roy Otten Memorial Airfield |
| West Branch Community (WBK) | West Branch | MI | Walter A Duncan Field Illinois Valley Regional to West Branch Community |
| Roben-Hood (WBR) | Big Rapids | MI | Walter A Duncan Field Illinois Valley Regional to Roben-Hood |
| Baxter County (WMH) | Mountain Home | AR | Walter A Duncan Field Illinois Valley Regional to Baxter County |
| Grand Geneva Resort (XES) | Lake Geneva | WI | Walter A Duncan Field Illinois Valley Regional to Grand Geneva Resort |
| Chatham-Kent Municipal (YCK) | Chatham | ON | Walter A Duncan Field Illinois Valley Regional to Chatham-Kent Municipal |
| Willow Run (YIP) | Detroit | MI | Walter A Duncan Field Illinois Valley Regional to Willow Run |
| Pelee Island (YPT) | Pelee Island | ON | Walter A Duncan Field Illinois Valley Regional to Pelee Island |
| Windsor (YQG) | Windsor | ON | Walter A Duncan Field Illinois Valley Regional to Windsor |
| Sarnia/Chris Hadfield (YZR) | Sarnia | ON | Walter A Duncan Field Illinois Valley Regional to Sarnia/Chris Hadfield |
| Zanesville Municipal (ZZV) | Zanesville | OH | Walter A Duncan Field Illinois Valley Regional to Zanesville Municipal |
