Airlines — K
- KDCK D Air Corporation
- KSAK S Avia
- KMIK-Mile Air
- QNKKabo Air
- KMCKahama Mining Corporation
- KAIKaiser Air
- KLSKal Star Aviation
- CKSKalitta Air
- KFSKalitta Charters
- KESKallat El Saker Air Company
- KMFKam Air
- KMPKampuchea Airlines
- KNDKan Air
- KIZKanaf-Arkia Airlines
- KHEKanfey Ha'emek Aviation
- KSUKansas State University
- KARKar-Air
- AKTKarat
- KRBKaribu Airways Company
- KLGKarlog Air Charter
- KAJKarthago Airlines
- KAEKartika Airlines
- KTVKata Transportation
- KTKKatekavia
- KATKato Airline
- MVDKavminvodyavia
- XKAKavouras Inc
- KRNKaz Agros Avia
- KAWKaz Air West
- KAOKazan Aviation Production Association
- KPHKazan Helicopters
- KKAKazavia
- KZSKazaviaspas
- KNIKD Avia
- JFKKeenair Charter -
- KLXKelix Air
- FKLKelner Airways
- KFAKelowna Flightcraft Air Charter
- KDAKendell Airlines
- KENKenmore Air
- KBAKenn Borek Air
- KAHKent Aviation
- KQAKenya Airways
- KVSKevis
- KWYKey Air
- KEYKey Airlines
- LYMKey Lime Air
- FTPKeystone Aerial Surveys
- KEEKeystone Air Services
- KZWKhalifa Airways
- KHKKharkiv Airlines
- WKHKharkov Aircraft Manufacturing Company
- KHRKhazar
- KHPKhoezestan Photros Air Lines
- KRVKhoriv-Avia
- KHOKhors Aircompany
- KHYKhyber Afghan Airlines
- KYVKibris T
- UAKKiev Aviation Plant
- KNGKing Aviation
- BEZKingfisher Air Services
- KFRKingfisher Airlines
- KASKingston Air Services
- KINKinloss Flying Training Unit
- KIPKinnarps
- KNSKinshasa Airways
- KTAKirov Air Enterprise
- IRKKish Air
- KHAKitty Hawk Aircargo
- KHCKitty Hawk Airways
- KIAKiwi International Air Lines
- KLCKLM Cityhopper
- KLHKLM Helicopter
- KLMKLM Royal Dutch Airlines
- KNAKnight Air
- KNXKnighthawk Air Express
- KHXKnighthawk Express
- KGTKnights Airlines
- KOAKoanda Avacion
- OYEKoda International
- KGLKogalymavia Air Company
- KOMKom Activity
- KMAKomiaviatrans State Air Enterprise
- KMVKomiinteravia
- KNMKomsomolsk-on-Amur Air Enterprise
- KOBKoob-Corp - 96 KFT
- KBRKoralBlue Airlines
- KEAKorea Express Air
- KALKorean Air
- KGOKorongo Airlines
- KMGKosmas Air
- KSMKosmos
- KOSKosova Airlines
- KOQKostromskie avialinii
- WOKKovar Air
- KJCKrasnojarsky Airlines
- KFCKremenchuk Flight College
- KRGKrimaviamontag
- KROKroonk Air Agency
- KRIKrylo Airlines