| NPT | KUUU | Newport State Airport | Newport | |
| WWT | PAEW | Newtok Airport | Newtok | |
| IAG | KIAG | Niagara Falls International Airport | Niagara Falls | |
| NME | PAGT | Nightmute Airport | Nightmute | |
| NIB | - | Nikolai Airport | Nikolai | |
| IKO | - | Nikolski Air Station | Nikolski | |
| WTK | PAWN | Noatak Airport | Noatak | |
| ARV | KARV | Noble F. Lee Airport | Minocqua | |
| OLS | KOLS | Nogales International Airport | Nogales | |
| NNL | - | Nondalton Airport | Nondalton | |
| SFZ | KSFZ | North Central State Airport | Pawtucket | |
| NZY | KNZY | North Island Naval Air Station | San Diego | |
| VGT | KVGT | North Las Vegas Airport | Las Vegas | |
| LBF | KLBF | North Platte Regional Airport (Lee Bird Field) | North Platte | |
| WWP | - | North Whale Sea Plane Base | Whale Pass | |
| PNE | KPNE | Northeast Philadelphia Airport | Philadelphia | |
| EDE | KEDE | Northeastern Regional Airport | Edenton | |
| MSL | KMSL | Northwest Alabama Regional Airport | Muscle Shoals | |
| OWD | KOWD | Norwood Memorial Airport | Norwood | |
| NUI | PAQT | Nuiqsut Airport | Nuiqsut | |
| NUL | - | Nulato Airport | Nulato | |
| NUP | - | Nunapitchuk Airport | Nunapitchuk | |
| - | KVCB | Nut Tree | Vacaville | |
| ONL | KONL | O'Neill Municipal Airport | O'Neill | |
| PTK | KPTK | Oakland County International Airport | Pontiac | |
| OCF | KOCF | Ocala International Airport | Ocala | |
| OCE | KOXB | Ocean City Municipal Airport | Ocean City | |
| OCA | - | Ocean Reef Airport | Ocean Reef | |
| CEU | KCEU | Oconee County Regional Airport | Clemson | |
| - | KODO | Odessa-Schlemeyer | Odessa | |
| OFF | KOFF | Offutt Air Force Base | Omaha | |
| OGS | KOGS | Ogdensburg Airport | Ogdensburg | |
| OSU | KOSU | Ohio State University Airport | Columbus | |
| OLH | - | Old Harbor Sea Plane Base | Old Harbor | |
| KOY | - | Olga Bay Sea Plane Base | Olga Bay | |
| OLV | KOLV | Olive Branch Airport | Olive Branch | |
| OLM | KOLM | Olympia Regional Airport | Olympia | |
| OMK | KOMK | Omak Municipal Airport | Omak | |
| RHI | KRHI | Oneida County Airport | Rhinelander | |
| ONO | KONO | Ontario Airport | Ontario | |
| OPF | KOPF | Opa-locka Executive Airport | Miami | |
| ESD | KORS | Orcas Island Airport | Eastsound | |
| MLB | KMLB | Orlando Melbourne International Airport | Melbourne | |
| SFB | KSFB | Orlando Sanford International Airport | Orlando | |
| FMH | KFMH | Otis Air Force Base | Falmouth | |
| KOZ | - | Ouzinkie Sea Plane Base | Ouzinkie | |
| OXR | KOXR | Oxnard Airport | Oxnard | |
| PGA | KPGA | Page Airport | Page | |
| FMY | KFMY | Page Field | Fort Myers | |
| PCE | - | Painter Creek Airport | Painter Creek | |