|-
|
|OCN
|
O Air
|O-BIRD
|France
|
|-
|UQ
|OCM
|
O'Connor Airlines
|OCONNOR
|Australia
|Defunct - Bankrupt
|-
|CR
|
|
OAG
|
|United Kingdom
|
|-
|
|JPA
|
OSACOM
|J-PAT
|United States
|
United States Army
|-
|O8
|OHK
|
Oasis Hong Kong Airlines
|OASIS
|Hong Kong
|
|-
|
|BCN
|
Ocean Air
|BLUE OCEAN
|Mauritania
|
|-
|VC
|VCX
|
Ocean Airlines
|OCEANCARGO
|Italy
|
|-
|
|OCS
|
Ocean Sky (UK)
|OCEANSKY
|United Kingdom
|
|-
|
|TUK
|
Ocean Wings Commuter Service
|TUCKERNUCK
|United States
|New Island Connections
|-
|O6
|ONE
|
Oceanair
|OCEANAIR
|Brazil
|
|-
|O2
|
|
Oceanic Airlines
|
|Guinea
|
|-
|
|ODS
|
Odessa Airlines
|ODESSA AIR
|Ukraine
|
|-
|
|ODY
|
Odyssey International
|ODYSSEY
|Canada
|
|-
|
|FOC
|
Office Federal De'Aviation Civile
|FOCA
|Switzerland
|
|-
|
|GBO
|
Ogooue Air Cargo
|
|Gabon
|
|-
|
|OKJ
|
Okada Airlines
|OKADA AIR
|Nigeria
|
|-
|
|OKP
|
Okapi Airways
|OKAPI
|Democratic Republic of Congo
|
|-
|
|OKA
|
Okay Airways
|OKAYJET
|China
|
|-
|
|OKL
|
Oklahoma Department of Public Safety
|OKLAHOMA
|United States
|Troop O
|-
|
|OLX
|
Olimex Aerotaxi
|OLIMEX
|Czech Republic
|
|-
|
|KVK
|
Olimp Air
|PONTA
|Kazakhstan
|
|-
|OA
|OAL
|
Olympic Airlines
|OLYMPIC
|Greece
|
|-
|
|OLY
|
Olympic Aviation
|OLAVIA
|Greece
|
|-
|WY
|OMA
|
Oman Air
|OMAN AIR
|Oman
|
|-
|
|ORF
|
Oman Royal Flight
|OMAN
|Oman
|
|-
|
|OAV
|
Omni - Aviacao e Tecnologia
|OMNI
|Portugal
|
|-
|OY
|OAE
|
Omni Air International
|OMNI-EXPRESS
|United States
|
|-
|
|OMF
|
Omniflys
|OMNIFLYS
|Mexico
|
|-
|N3
|OMS
|
Omskavia Airline
|OMSK
|Russia
|
|-
|
|ORL
|
On Air Limited
|ON AIR
|Canada
|
|-
|
|OTG
|
One Two Go Airlines
|THAI EXPRESS
|Thailand
|
|-
|
|OTM
|
Onetime Airlines Zambia
|ZEDTIME
|Zambia
|
|-
|
|MED
|
Ontario Ministry of Health
|MEDICAL
|Canada
|
|-
|8Q
|OHY
|
Onur Air
|ONUR AIR
|Turkey
|
|-
|
|OPA
|
Opal Air
|
|Australia
|
|-
|
|OSA
|
Open Sky Aviation
|
|Lebanon
|
|-
|
|BOS
|
OpenSkies
|MISTRAL
|United Kingdom
|
|-
|
|ORR
|
Operadora Turistica Aurora
|TURISTICA AURORA
|Mexico
|
|-
|
|OLE
|
Operadora de Lineas Ejecutivas
|OPERADORA
|Mexico
|
|-
|
|OTP
|
Operadora de Transportes Aereos
|OPERADORA AEREO
|Mexico
|
|-
|
|OPV
|
Operadora de Veulos Ejectutivos
|OPERADORA DE VUELOS
|Mexico
|
|-
|
|LLO
|
Operation Enduring Freedom
|APOLLO
|Canada
|
|-
|
|OAX
|
Operational Aviation Services
|
|Australia
|
|-
|
|ORD
|
Orange Air Services
|ORANGE SERVICES
|Sierra Leone
|
|-
|
|ORJ
|
Orange Air Sierra Leone
|ORANGE SIERRA
|Sierra Leone
|
|-
|
|ORE
|
Orange Aviation
|ORANGE AVIATION
|Israel
|
|-
|
|ORX
|
Orbit Express Airlines
|OREX
|Turkey
|
|-
|
|ORK
|
Orca Air
|ORCA TAXI
|Egypt
|
|-
|
|BUE
|
Orebro Aviation
|BLUELIGHT
|Sweden
|
|-
|
|ORM
|
Orel State Air Enterprise
|ORPRISE
|Russia
|
|-
|R2
|ORB
|
Orenburg Airlines
|ORENBURG
|Russia
|
|-
|
|OTA
|
Organizacion De Transportes Aereos
|ORGANIZACION
|Mexico
|
|-
|
|OML
|
Organizacoes Mambra
|MAMBRA
|Angola
|
|-
|
|OVV
|
Orient Air
|ORIENTSYR
|Syrian Arab Republic
|
|-
|
|OTR
|
Orient Airlines
|ORIENTROC
|Sudan
|
|-
|
|ORN
|
Orient Airways
|ORIENT LINER
|Pakistan
|
|-
|OX
|OEA
|
Orient Thai Airlines
|ORIENT THAI
|Thailand
|
|-
|
|NGK
|
Oriental Air Bridge
|ORIENTAL BRIDGE
|Japan
|
|-
|
|OAC
|
Oriental Airlines
|ORIENTAL AIR
|Nigeria
|
|-
|QO
|OGN
|
Origin Pacific Airways
|ORIGIN
|New Zealand
|
|-
|
|OED
|
Orion Air Charter
|ORION CHARTER
|South Africa
|
|-
|
|OIX
|
Orion-x
|ORIONIX
|Russia
|
|-
|
|KOV
|
Orlan-2000
|ORLAN
|Kazakhstan
|
|-
|
|RNG
|
Ornage Aircraft Leasing
|ORANGE
|Netherlands
|
|-
|
|OAD
|
Orscom Tourist Installations Company
|ORSCOM
|Egypt
|
|-
|
|OSH
|
Osh Avia
|OSH AVIA
|Kyrgyzstan
|
|-
|
|OCO
|
Ostend Air College
|AIR COLLEGE
|Belgium
|
|-
|OL
|OLT
|
Ostfriesische Lufttransport
|OLTRA
|Germany
|
|-
|
|FNL
|
Oulun Tilauslento
|FINN FLIGHT
|Finland
|
|-
|ON
|RON
|
Our Airline
|OUR AIRLINE
|Nauru
|formerly
Air Nauru
|-
|
|OOT
|
Out Of The Blue Air Safaris
|OOTBAS
|South Africa
|
|-
|OJ
|OLA
|
Overland Airways
|OVERLAND
|Nigeria
|
|-
|
|OXE
|
Oxaero
|OXOE
|United Kingdom
|
|-
|
|WDK
|
Oxford Air Services
|WOODSTOCK
|United Kingdom
|
|-
|
|OAA
|
Oxley Aviation
|
|Australia
|
|-
|OZ
|OZR
|
Ozark Air Lines
|OZARK
|United States
|defunct
|-
|O7
|OZJ
|
Ozjet Airlines
|AUSJET
|Australia
|
