| 69WA | O & M Facilities Heliport | Clarkston WA |
| 05CT | O And G Heliport | Torrington CT |
| 64OH | O K Dies Airport | Salem OH |
| 28IS | O K Flying Club Inc Airport | Fillmore IL |
| 14TS | O S Wyatt Airport | Realitos TX |
| OH23 | O'bleness Memorial Hospital Heliport | Athens OH |
| FD71 | O'brien Airpark East/west Airport | Branford FL |
| LA71 | O'brien Flying Service Airport | Iowa LA |
| 8IL5 | O'connor Field Airport | Pecatonica IL |
| VA40 | O'gara Tech Training Facility Heliport | Danville VA |
| NY71 | O'riley Airport | Fort Plain NY |
| CSL | O'sullivan Ahp Heliport | Camp San Luis Obispo CA |
| NV02 | O'toole Ranch Airport | Austin NV |
| TE69 | Oak Bend Medical Center Heliport | Richmond TX |
| 33CL | Oak Country Ranch Airport | Paso Robles CA |
| 3TS9 | Oak Glen Ranch Airport | Cooper TX |
| 13NC | Oak Grove Mcolf Airport | Pollocksville NC |
| FA73 | Oak Harbor Seaplane Base | Haines City FL |
| OH72 | Oak Hill Hospital Heliport | Oak Hill OH |
| MN42 | Oak Lake Air Strip Airport | Erskine MN |
| 16LL | Oak Landing Heliport | Bull Valley IL |
| FL82 | Oak Ridge Airport | Interlachen FL |
| NY16 | Oak Ridge Airport | East Palmyra NY |
| 4TA7 | Oak Ridge Heliport | Ingleside TX |
| MO80 | Oak Ridge Airpark Airport | Mountain Grove MO |
| 5MO9 | Oak Ridge Farms Airport | New Boston MO |
| 13GA | Oak Ridge Plantation Airport | Sylvester GA |
| 6J8 | Oak Tree Landing Airport | High Springs FL |
| 47WI | Oakbrook Airport | Fort Atkinson WI |
| O27 | Oakdale Airport | Oakdale CA |
| 16PN | Oakdale Ahp Heliport | Oakdale PA |
| 66IN | Oakes Field Airport | Charlottesville IN |
| 2D5 | Oakes Muni Airport | Oakes ND |
| 75DC | Oakesdale Airport | Oakesdale WA |
| SC82 | Oakhill Airpark Airport | Williamson SC |
| CL41 | Oakland Convention Center Heliport | Oakland CA |
| PTK | Oakland County Intl Airport | Pontiac MI |
| Y47 | Oakland Southwest Airport | New Hudson MI |
| VLL | Oakland/troy Airport | Troy MI |
| 9SD8 | Oakleaf Airport | Hartford SD |
| TN79 | Oakley Airport | Nashville TN |
| 1U6 | Oakley Muni Airport | Oakley ID |
| OEL | Oakley Muni Airport | Oakley KS |
| 26OG | Oakridge Ranch Airport | Eagle Point OR |
| 5S0 | Oakridge State Airport | Oakridge OR |
| TX24 | Oaks Airport | Arp TX |
| SC52 | Oakview Airport | Six Mile SC |
| 05MI | Oakwood Heritage Hospital Heliport | Taylor MI |
| 56MI | Oakwood Hospital Heliport | Dearborn MI |
| 9FL7 | Oasis Ranger Station-u.s. Government Airport | Everglades City FL |
| OH66 | Obannon Creek Aerodrome Airport | Goshen OH |
| PA52 | Oberlander Airport | Union City PA |
| OIN | Oberlin Muni Airport | Oberlin KS |
| 7OH3 | Obi One Airport | Delaware OH |
| OCF | Ocala Intl-jim Taylor Field Airport | Ocala FL |
| 44CN | Occidental Petroleum Heliport | Los Angeles CA |
| 7WA9 | Ocean Beach Hospital Heliport | Ilwaco WA |
| 23FA | Ocean Beach Resort Heliport | Miami Beach FL |
| OXB | Ocean City Muni Airport | Ocean City MD |
| 26N | Ocean City Muni Airport | Ocean City NJ |
| MJX | Ocean County Airport | Toms River NJ |
| 07FA | Ocean Reef Club Airport | Key Largo FL |
| E55 | Ocean Ridge Airport | Gualala CA |
| W04 | Ocean Shores Muni Airport | Ocean Shores WA |
| 5R2 | Ocean Springs Airport | Ocean Springs MS |
| C04 | Oceana County Airport | Hart/shelby MI |
| NTU | Oceana Nas /apollo Soucek Field/ Airport | Virginia Beach VA |
| L52 | Oceano County Airport | Oceano CA |
| OKB | Oceanside Muni Airport | Oceanside CA |
| 42MS | Och Rgnl Medical Center Heliport | Starkville MS |
| 6WA4 | Ochoa Fld Airport | Othello WA |
| 72OR | Ochs Private Airport | Madras OR |
| NE62 | Ochsner Heliport | Madison NE |
| LS51 | Ochsner Medical Center Northshore Heliport | Slidell LA |
| LS96 | Ochsner Medical Institutions Heliport | Jefferson LA |
| 7LA2 | Ochsner St Anne General Hospital Heliport | Raceland LA |
| DE23 | Ockel Farms Airport | Milton DE |
| CEU | Oconee County Rgnl Airport | Clemson SC |
| 0WI8 | Oconomowoc Airport | Oconomowoc WI |
| L90 | Ocotillo Airport | Ocotillo Wells CA |
| W95 | Ocracoke Island Airport | Ocracoke NC |
| 57ND | Odegaard Airport | Kindred ND |
| 60J | Odell Williamson Muni Airport | Ocean Isle Beach NC |
| 9WA2 | Odessa Memorial Hospital Ems Heliport | Odessa WA |
| 43D | Odessa Muni Airport | Odessa WA |
| ODO | Odessa-schlemeyer Field Airport | Odessa TX |
| AR28 | Odom Field Airport | Cabot AR |
| 50FL | Odom's Flying Service Airport | Jay FL |
| 76OK | Odom's Roost Airport | Newcastle OK |
| 1OH6 | Odot Heliport | Sidney OH |
| 60OH | Odot Dist 4 Office Heliport | Ravenna OH |
| 5OH2 | Odot District 03 Heliport | Ashland OH |
| OH84 | Odot District Nr 1 Heliport | Lima OH |
| 01WT | Odyssey Heliport | Renton WA |
| OLZ | Oelwein Muni Airport | Oelwein IA |
| 1AK5 | Offshore Systems-kenai Heliport | Nikiski AK |
| PN02 | Offutt Acres Airport | East Brady PA |
| OFF | Offutt Afb Airport | Omaha NE |
| Z08 | Ofu Airport | Ofu Village AS |
| NE14 | Ogallala Community Hospital Heliport | Ogallala NE |
| 54UT | Ogden Regional Medical Center Heliport | Washington Terrace UT |
| OGD | Ogden-hinckley Airport | Ogden UT |
| OGS | Ogdensburg Intl Airport | Ogdensburg NY |
| C55 | Ogle County Airport | Mount Morris IL |
| MT87 | Oglesby Farms Inc Airport | Peerless MT |
| 0XA8 | Ohho Airport | Dripping Springs TX |
| OH53 | Ohio Bldg Authority Heliport | Columbus OH |
| JQD | Ohio County Airport | Hartford KY |
| 6C2 | Ohio Dusting Co Inc Airport | Pandora OH |
| OSU | Ohio State University Airport | Columbus OH |
| OH54 | Ohio State University Hospital Heliport | Columbus OH |
| UNI | Ohio University Snyder Field Airport | Athens/albany OH |
| PS10 | Ohioport Heliport | Ohiopyle PA |
| E14 | Ohkay Owingeh Airport | Espanola NM |
| WY12 | Ohman Ranch Airport | Gillette WY |
| D11 | Ojibwa Airpark Airport | Weidman MI |
| S35 | Okanogan Legion Airport | Okanogan WA |
| 3OK1 | Okarche Airport | Okarche OK |
| OBE | Okeechobee County Airport | Okeechobee FL |
| FL41 | Okeelanta Airport | South Bay FL |
| 3GE1 | Okefenokee Heliport | Folkston GA |
| F81 | Okemah Flying Field Airport | Okemah OK |
| 7MO7 | Okie Dokie Airport | Golden City MO |
| 77OK | Oklahoma National Guard Heliport | Oklahoma City OK |
| OKM | Okmulgee Rgnl Airport | Okmulgee OK |
| 5A4 | Okolona Muni-richard Stovall Field Airport | Okolona MS |
| DE33 | Okolona Plantation Airport | Middletown DE |
| M51 | Oktibbeha Airport | Starkville MS |
| 03ND | Olafson Brothers Airport | Edinburg ND |
| D80 | Olcott-newfane Airport | Olcott NY |
| 70OK | Old 66 Strip Airport | Miami OK |
| 02ME | Old Acton Airfield Airport | Acton ME |
| 9CL7 | Old Aerodrome Airport | Marysville CA |
| 3N6 | Old Bridge Airport | Old Bridge NJ |
| 3WN2 | Old Dairy Airport | Washburn WI |
| NK26 | Old Forge Airport | Old Forge NY |
| TA30 | Old Forker Ultralight | Sante Fe TX |
| 50NY | Old Fort Farm Airport | Hemlock NY |
| 6R7 | Old Harbor Airport | Old Harbor AK |
| 56LA | Old Hickory Ranch Airport | Keithville LA |
| 67T | Old Hoppe Place Airport | Agua Dulce TX |
| 85TE | Old Kingsbury Aerodrome Airport | Kingsbury TX |
| 0PS4 | Old Orchard Airport | Curwensville PA |
| 2NK9 | Old Orchard Airpark Airport | Modena NY |
| 9PA2 | Old Plains Airport | Pennsburg PA |
| 6NY1 | Old Port Royal Airport | Corning NY |
| 4P2 | Old Portage Heliport | Akron OH |
| 5XS6 | Old Reb Airport | Mercedes TX |
| NY94 | Old Rhinebeck Airport | Rhinebeck NY |
| 32VA | Old South Aerodrome Airport | Abingdon VA |
| 0FL3 | Old Town Ems Heliport | Old Town FL |
| 27IA | Oldfield Aero Airport | Keosauqua IA |
| E52 | Oldham County Airport | Vega TX |
| 5NK4 | Olean General Heliport | Olean NY |
| 4II3 | Oleo Airport | Fillmore IN |
| MT04 | Olfert Airport | Lustre MT |
| KOY | Olga Bay Seaplane Base | Olga Bay AK |
| OR81 | Olinger Airpark Airport | Hillsboro OR |
| OLV | Olive Branch Airport | Olive Branch MS |
| CA64 | Olive View Medical Center Heliport | Sylmar CA |
| 4TX7 | Oliver Airport | Knox City TX |
| 42TN | Oliver Landing Airport | Paris TN |
| TN08 | Oliver Springs Inc Airport | Oliver Springs TN |
| IS92 | Olivers Heliport | Gilberts IL |
| OVL | Olivia Rgnl Airport | Olivia MN |
| L47 | Olla Airport | Olla LA |
| SD97 | Oller Airport | Vivian SD |
| 73NY | Olmstead Landing Strip Airport | Masonville NY |
| ID25 | Olmstead Sky Ranch Airport | Sandpoint ID |
| ONY | Olney Muni Airport | Olney TX |
| OLY | Olney-noble Airport | Olney-noble IL |
| 5IL1 | Olson Heliport | Pecatonica IL |
| LL53 | Olson Airport | Plato Center IL |
| SN40 | Olson Aerodrome Airport | Derby KS |
| NE30 | Olson Field Airport | Holdrege NE |
| 3WI1 | Olson's Airport | Union Grove WI |
| 83IL | Oltman-shuck Airport | Minonk IL |
| F09 | Olustee Muni Airport | Olustee OK |
| 0WN4 | Olympia Heliport | Olympia WA |
| OLM | Olympia Rgnl Airport | Olympia WA |
| WA45 | Olympic Field Airport | Discovery Bay/maynard WA |
| 26WA | Olympic Memorial Hospital Heliport | Port Angeles WA |
| OMK | Omak Airport | Omak WA |
| 6MI8 | Omans Heliport | Almont MI |
| MBY | Omar N Bradley Airport | Moberly MO |
| 12CO | Omega 1 Airport | Hotchkiss CO |
| 9OK1 | Omh Heliport | Oklahoma City OK |
| LS13 | Omni Heliport | Carencro LA |
| LA46 | Omni Airport | Port Allen LA |
| 6NY2 | Omni Airpark Airport | Horseheads NY |
| 18LS | Omni Mouton Cove Heliport | Abbeville LA |
| 49XA | Omni Ranch Ultralight | Edinburg TX |
| WI85 | Omniflight Helicopters Heliport | Janesville WI |
| 1CA6 | On The Rocks Airport | Alpine CA |
| 12V | Ona Airpark Airport | Milton WV |
| K36 | Onawa Muni Airport | Onawa IA |
| 5TN9 | One Grand Field Airport | Cookeville TN |
| 10PN | One Meridian Plaza Heliport | Philadelphia PA |
| 9TS1 | One O'connor Plaza-tower Heliport | Victoria TX |
| 77KY | One Oak Airport | Mount Sterling/owingsville KY |
| NK39 | One Police Plaza Heliport | New York NY |
| TS02 | One Sixty Four Place Airport | Jacksboro TX |
| NK22 | One Ten Heliport | Farmingdale NY |
| N66 | Oneonta Muni Airport | Oneonta NY |
| 98D | Onida Muni Airport | Onida SD |
| 43NE | Onion Crest Airpark Airport | Riverdale NE |
| VG20 | Onley Airport | Onley VA |
| NK55 | Onondaga County Sheriff's Department Heliport | Camillus NY |
| ONT | Ontario Intl Airport | Ontario CA |
| ONO | Ontario Muni Airport | Ontario OR |
| OGM | Ontonagon County - Schuster Field Airport | Ontonagon MI |
| VT43 | Onyon Airport | Townshend VT |
| SC75 | Oolenoy Valley Airport | Pickens SC |
| AK32 | Oooguruk Island Heliport | Nuiqsut AK |
| OPF | Opa-locka Executive Airport | Miami FL |
| 80TE | Opela Heliport | Carrollton TX |
| 3LA8 | Open A-1 Ranch Airport | Lake Charles LA |
| CN39 | Operating Engineers Pension Trust Bldg Heliport | Los Angeles CA |
| PS44 | Operations Center Heliport | Bellwood PA |
| S00 | Opheim Airport | Opheim MT |
| Z17 | Ophir Airport | Ophir AK |
| CA85 | Opus Center Irvine Heliport | Irvine CA |
| PR14 | Orama-iayuya Heliport | Jayuya PR |
| ORC | Orange City Muni Airport | Orange City IA |
| 6CL7 | Orange Co Sheriffs Forensics Lab Helistop Heliport | Santa Ana CA |
| MGJ | Orange County Airport | Montgomery NY |
| ORG | Orange County Airport | Orange TX |
| OMH | Orange County Airport | Orange VA |
| 27FA | Orange County Sheriff's Office Heliport | Orlando FL |
| CL44 | Orange County Steel Salvage Heliport | Anaheim CA |
| NOG | Orange Grove Nalf Airport | Orange Grove TX |
| 15FD | Orange Hill Airport | Wausau FL |
| ORE | Orange Muni Airport | Orange MA |
| 20FA | Orange Park Medical Center Heliport | Orange Park FL |
| 4NY1 | Orange Poultry Farm Airport | Chester NY |
| 6NY0 | Orange Rgnl Medical Center Heliport | Middletown NY |
| OGB | Orangeburg Muni Airport | Orangeburg SC |
| 34WA | Orbit Heliport | Washougal WA |
| ORS | Orcas Island Airport | Eastsound WA |
| WY38 | Orchard Ranch Airport | Ten Sleep WY |
| 5CA2 | Ord Mountain Heliport | Barstow CA |
| MS88 | Oreck Airport | Poplarville MS |
| 9OR6 | Oregon Health Sciences University Emerg Heliport | Portland OR |
| OG33 | Oregon Sky Ranch Airport | Milton/freewater OR |
| FA08 | Orlampa Inc Airport | Polk City FL |
| X04 | Orlando Apopka Airport | Apopka FL |
| MCO | Orlando Intl Airport | Orlando FL |
| FA83 | Orlando North Airpark Airport | Zellwood FL |
| FD28 | Orlando Rgnl Medical Center Heliport | Orlando FL |
| SFB | Orlando Sanford Intl Airport | Orlando FL |
| 6FA8 | Orlando Sun Resort Heliport | Kissimmee FL |
| 7I4 | Orleans Airport | Orleans IN |
| 3FD1 | Ormc Trauma Center Heliport | Ocala FL |
| OMN | Ormond Beach Muni Airport | Ormond Beach FL |
| PR19 | Orocovis Health Center Heliport | Orocovis PR |
| S68 | Orofino Muni Airport | Orofino ID |
| 75C | Orogrande Airport | Orogrande ID |
| OVE | Oroville Muni Airport | Oroville CA |
| 24NE | Orr Airport | Lakeside NE |
| NE25 | Orr Field Airport | North Platte NE |
| 33NE | Orr Ranch Airport | Hay Springs NE |
| ORB | Orr Rgnl Airport | Orr MN |
| 7PA4 | Orson Field Airport | Orson PA |
| I64 | Ortner Airport | Wakeman OH |
| 50MN | Ortonville Hospital Heliport | Ortonville MN |
| VVV | Ortonville Muni-martinson Field Airport | Ortonville MN |
| 86NE | Orum Aerodrome Airport | Blair NE |
| 53K | Osage City Muni Airport | Osage City KS |
| D02 | Osage Muni Airport | Osage IA |
| 02FA | Osborn Airfield Airport | Groveland FL |
| 8CA0 | Osborne Airport | Victorville CA |
| K75 | Osborne Muni Airport | Osborne KS |
| IA40 | Osceola Community Hospital Heliport | Sibley IA |
| 7M4 | Osceola Muni Airport | Osceola AR |
| I75 | Osceola Muni Airport | Osceola IA |
| 23MU | Osceola Muni Airport | Osceola MO |
| 12FD | Osceola Rgnl Hospital Heliport | Kissimmee FL |
| 19FD | Osceola Sheriff's Ofc - Bronson Hwy Heliport | Kissimmee FL |
| 51M | Oscoda County Dennis Kauffman Memorial Airport | Mio MI |
| OSC | Oscoda-wurtsmith Airport | Oscoda MI |
| 80E | Oscura Aaf Aux Airport | Oscura NM |
| LL01 | Osf Holy Family Medical Center Heliport | Monmouth IL |
| LL37 | Osf Saint Francis Medical Center Heliport | Peoria IL |
| LL25 | Osf St Elizabeth Medical Center Heliport | Ottawa IL |
| IL40 | Osf St Joseph Medical Center Heliport | Bloomington IL |
| IL89 | Osf St Mary Medical Center - Galesburg Heliport | Galesburg IL |
| OOA | Oskaloosa Muni Airport | Oskaloosa IA |
| XA49 | Oso Canyon Airport | Ozona TX |
| 78WI | Osseo Medical Center Heliport | Osseo WI |
| 4TS9 | Ossiport Heliport | Austin TX |
| 40NJ | Osterman Heliport | Neshanic NJ |
| FZY | Oswego County Airport | Fulton NY |
| 05NY | Oswego County At Pulaski Heliport | Pulaski NY |
| K67 | Oswego Muni Airport | Oswego KS |
| 72NM | Otero Mill Airport | La Luz NM |
| 24WA | Othello Community Hospital Heliport | Othello WA |
| S70 | Othello Muni Airport | Othello WA |
| CT71 | Otis Helistop Division Of Utc Heliport | Farmington CT |
| 7TS8 | Ott Farms Airport | Dimmitt TX |
| Z98 | Ottawa Executive Airport | Zeeland MI |
| OWI | Ottawa Muni Airport | Ottawa KS |
| 81LL | Otterbach Farm Airport | Mendota IL |
| 5WN9 | Ottman Landing Airport | Maiden Rock WI |
| 62TE | Otto Kaiser Hospital Heliport | Kenedy TX |
| 3IA6 | Ottumwa Hospital Heliport | Ottumwa IA |
| OTM | Ottumwa Rgnl Airport | Ottumwa IA |
| 11OK | Ou Medical Center Edmond Heliport | Edmond OK |
| AR42 | Ouachita County Medical Center Heliport | Camden AR |
| 0NC6 | Our Community Hospital Heliport | Scotland Neck NC |
| 7MD0 | Our Domain Airport | Marydel MD |
| 6KY9 | Our Lady Of Bellefonte Hospital Heliport | Russell KY |
| 48LS | Our Lady Of Lourdes Rgnl Medical Center Heliport | Lafayette LA |
| 29LA | Our Lady Of The Lake R.m.c. Heliport | Baton Rouge LA |
| 22NJ | Our Lady's Heliport | Mount Holly NJ |
| MT94 | Ousel Falls Airport | Big Sky MT |
| ATW | Outagamie County Rgnl Airport | Appleton WI |
| 5XS7 | Outback Airport | Lockney TX |
| AZ01 | Outback Ranch Airstrip Airport | Wenden AZ |
| NC88 | Outer Banks Heliport | Nags Head NC |
| CKV | Outlaw Field Airport | Clarksville TN |
| 16XS | Outlaw Flyers Airport | Conroe TX |
| 4K5 | Ouzinkie Airport | Ouzinkie AK |
| 12SC | Over The Hill Airport | Elgin SC |
| MI14 | Overflow Pad (lower Pad) Heliport | Ann Arbor MI |
| 1WT6 | Overlake Hospital Ems Heliport | Bellevue WA |
| SN54 | Overland Park Rgnl Medical Center Heliport | Overland Park KS |
| 27ND | Overland-lohse Field Airport | Alamo ND |
| CO75 | Overlook Athletic Club Heliport | Breckenridge CO |
| 4LA8 | Overton Private Airport | Clinton LA |
| D82 | Ovid Airport | Ovid NY |
| Y92 | Owasco Airport | Moravia NY |
| OWA | Owatonna Degner Rgnl Airport | Owatonna MN |
| NK49 | Owego Heliport | Owego NY |
| 0KY0 | Owen Air Park Airport | Owenton KY |
| MT01 | Owen Bros Airport | Geraldine MT |
| 20AK | Owen Field Airport | Big Lake AK |
| H58 | Owen Field Airport | Seymour MO |
| 4XA3 | Owen Field Airport | Clyde TX |
| ID39 | Owen Ranches Inc Airport | Bruneau ID |
| WS42 | Owen-withee Airport | Withee WI |
| 15TS | Owens Country Sausage Heliport | Richardson TX |
| II29 | Owens Field Airport | Greencastle IN |
| OWB | Owensboro-daviess County Airport | Owensboro KY |
| 9MO8 | Owensville Ambulance District Heliport | Owensville MO |
| 4CO2 | Owl Canyon Gliderport | Wellington CO |
| CD81 | Owl Ridge Heliport | Walden CO |
| RNP | Owosso Community Airport | Owosso MI |
| 10U | Owyhee Airport | Owyhee NV |
| 28U | Owyhee Reservoir State Airport | Owyhee OR |
| 04WA | Ox Meadows Airport | Spokane WA |
| OR12 | Oxbow Airport | Homestead OR |
| OR83 | Oxbow Heliport | Oxbow Village OR |
| MA73 | Oxbow Corporation Heliport | Dover MA |
| OR17 | Oxbow Ranch Airport | Prairie City OR |
| 81B | Oxford County Rgnl Airport | Oxford ME |
| 55K | Oxford Muni Airport | Oxford KS |
| OXR | Oxnard Airport | Oxnard CA |
| 5NJ8 | Oyster Creek Generating Station Heliport | Forked River NJ |
| 2KY4 | Oz Airport | Elizabethtown KY |
| AR11 | Ozark Aerodrome Airport | Rogers AR |
| 05AR | Ozark Skies Airpark Airport | Kingston AR |
| 7M5 | Ozark-franklin County Airport | Ozark AR |
| 74MO | Ozarkcom Army Heliport | St Louis MO |
| 0AR4 | Ozarks Community Hospital Heliport | Gravette AR |
| 50MO | Ozarks Medical Center Heliport | West Plains MO |
| OZA | Ozona Muni Airport | Ozona TX |
