 | Korean Air | 1962 | 159 |
 | KLM | 1919 | 116 |
 | KLM Cityhopper | 1991 | 46 |
 | Kenya Airways | 1977 | 34 |
 | Kuwait Airways | 1954 | 23 |
 | Kunming Airlines | 2009 | 14 |
 | Kish Air | 1991 | 12 |
 | Kal Star Aviation | 2000 | 12 |
 | Kam Air | 2003 | 6 |
 | Kabo Air | 1981 | 4 |
 | K-Mile Air Co. Ltd | - | 2 |
 | Kalitta Charters, L.L.C. | 2001 | 2 |
 | Kelowna Flightcraft Air Charter | - | 1 |
 | Key Lime Air Corporation | 1997 | 1 |
 | Kannithi Aviation Company Limited d Kan Air | 2010 | 1 |
 | Kolavia | 2012 | 1 |
 | Korea Express Air | 2015 | 1 |
| KlasJet | - | - |
| Kingfisher Air Services | - | - |
| Kosmos Airlines | - | - |
| Kovar Air | - | - |
| Khaan Airlines | - | - |
| Khyber Afghan Airlines | - | - |
| Kommunalf�rbundet Ambulanshelikopter V�rmland-Dalarna | - | - |
| Kapital Aviation | - | - |
| Koda International | - | - |
| Karibu Airways | - | - |
| Kermas Aviation | - | - |
| Koral Blue | - | - |
| Kaua Transportes Aereos | - | - |
| Kharkov Aircraft Manufacturing Company | - | - |
 | Karinou Airlines | - | - |
| Kotlas Air | - | - |
| Kahama Mining Corporation | - | - |
| Kinnarps | - | - |
| Key Air | - | - |
| Kingston Air Services | - | - |
| Korea National University of Transportation | - | - |
| Kwena Air, South African Charter | - | - |
| Kansas State University | - | - |
| Kevis | - | - |
| Kremenchuk Flight College | - | - |
| Kelix Air | - | - |
| KD Air | - | - |
| Kaliningrad Air Enterprise | - | - |
| Kavouras | - | - |
| Khazar | - | - |
| Kush Aviation | - | - |
| Kun Peng Airlines | - | - |
| Kosovaair | - | - |
| Knighthawk Express | - | - |
| Kostroma Air Enterprise | - | - |
| Kudlik Aviation | - | - |
 | KAPO Avia | - | - |
| Khoriv-Avia, State Enterprise | - | - |
| Kaya Airlines | - | - |
| Kyrgyz General Aviation | - | - |
| K5-Aviation | - | - |
 | Krasavia | - | - |
 | Katmai Air | - | - |
| Karthago Private Jet | - | - |
| Kura Kura Aviation | - | - |
| Kokshetau Airlines | - | - |
| Kolob Canyons Air Services | - | - |
| Kaz Air Jet | - | - |
| Keystone Air | - | - |
| Kinloss FTU | - | - |
 | Kartika Airlines | - | - |
| Khozestan Photros Air Lines | - | - |
| Kitty Hawk Airways | - | - |
| Kiss Air | - | - |
| K2 SmartJets | - | - |
| Kazan Plant Of Helicopters | - | - |
| Korea Aviation College | - | - |
| Khatlon Air | - | - |
| Kenmore Crew Leasing | - | - |
| Keystone Aerial Surveys | - | - |
| Kent Aviation | - | - |
| Kustbevakningen | - | - |
| KGFM Transport And Logistics | - | - |
 | Kinda Airlines | - | - |
 | Kazaviaspas | - | - |
| Kyrgyz Airlines | - | - |
| Kansas Highway Patrol | - | - |
| Kata Transportation Company | - | - |
 | Keen Airways | - | - |
| Kyungwoon University | - | - |
| Kaz Air West | - | - |
| Kvadro Aero | - | - |
| Kaiser Air | - | - |
| K5 Aviation | - | - |
| Korea Aviation | - | - |
| Karlog Air | - | - |
| Kazavia | - | - |
| Kavok Airlines | - | - |
| Kroonk, Air Agency | - | - |
 | Kato Airline | - | - |
| Kobo-Coop - 96 KFT | - | - |
| Kabul Air | - | - |
 | Kharkiv Airlines | - | - |
| Knights Airlines | - | - |
 | Kenmore Air | 1946 | - |
 | Kenn Borek Air Ltd. | 1970 | - |
| Kivalliq Air | 1998 | - |