- Cape Romanzof (CZF)
- Caribou (CAR)
- Carlsbad (CLD)
- Carlsbad (CNM)
- Carson City (CSN)
- Casper (CPR)
- Cedar City (CDC)
- Cedar Rapids (CID)
- Chadron (CDR)
- Chanute (CNU)
- Charles City (CCY)
- Charleston (CHS)
- Charleston (CRW)
- Charlotte (CLT)
- Charlottesville (CHO)
- Chattanooga (CHA)
- Cheyenne (CYS)
- Chicago (MDW)
- Chicago (ORD)
- Chicago/Prospect Heights/Wheeling (PWK)
- Chicago/Rockford (RFD)
- Chicago/West Chicago (DPA)
- Chicopee (CEF)
- Childress (CDS)
- Cincinnati (LUK)
- Cincinnati / Covington (CVG)
- Cleveland (BKL)
- Cleveland (CGF)
- Cleveland (CLE)
- Clovis (CVN)
- Clovis (CVS)
- Cocoa Beach (COF)
- Cody (COD)
- Coeur d'Alene (COE)
- Cold Bay (CDB)
- College Station (CLL)
- Colorado Springs (COS)
- Columbia (CAE)
- Columbia (COU)
- Columbia (CUB)
- Columbus (CBM)
- Columbus (CLU)
- Columbus (CMH)
- Columbus (CSG)
- Columbus (LCK)
- Columbus (OLU)
- Columbus (OSU)
- Columbus/W Point/Starkville (GTR)
- Concord (CCR)
- Concord (CON)
- Concord (USA)
- Cordova (CDV)
- Corpus Christi (CRP)
- Corpus Christi (NGP)
- Cortez (CEZ)
- Corvallis (CVO)
- Crescent City (CEC)
- Crestview (CEW)
- Crestview (EGI)
- Crossville (CSV)
- Cut Bank (CTB)
- Daggett (DAG)
- Dalhart (DHT)
- Dallas (DAL)
- Dallas-Fort Worth (DFW)
- Dallesport / The Dalles (DLS)
- Danbury (DXR)
- Danville (DAN)
- Dayton (DAY)
- Dayton (FFO)
- Daytona Beach (DAB)
- DeRidder (DRI)
- Deadhorse (SCC)
- Decatur (DEC)
- Deering (DRG)
- Del Rio (DLF)
- Del Rio (DRT)
- Delta Junction Ft Greely (BIG)
- Deming (DMN)
- Denison (PNX)
- Denver (APA)
- Denver (BJC)
- Denver (DEN)
- Des Moines (DSM)
- Destin (DSI)
- Detroit (DET)
- Detroit (DTW)
- Detroit (YIP)
- Devils Lake (DVL)
- Dickinson (DIK)
- Dillingham (DLG)
- Dodge City (DDC)
- Dothan (DHN)
- Douglas Bisbee (DUG)
- Dover (DOV)
- Dubois (DUJ)
- Dubuque (DBQ)
- Dulles (IAD)
- Duluth (DLH)
- Durango (DRO)
- Durant (DUA)
- Eagle (EGE)
- East Farmingdale (FRG)
- Eastover (MMT)
- Eastsound (ESD)
- Eau Claire (EAU)
- Edwards (EDW)
- Egegik (EGX)
- El Centro (NJK)
- El Dorado (ELD)
- El Paso (ELP)
- Elizabeth City (ECG)
- Elkins (EKN)
- Elko (EKO)
- Elmira/Corning (ELM)
- Ely (ELY)
- Ely (LYU)
- Emmonak (EMK)
- Enid (END)
- Erie (ERI)