| Name | What | Region | Country | Lat | Long | Elev ft. | Pop est |
|---|---|---|---|---|---|---|---|
| ON THE ROCKS | airport | United States | 32.77 | -116.72 | 2650 | 0 | |
| ONA (WINONA MUNI MAX CONRAD FLD) | airport | United States | 44.08 | -91.71 | 656 | 0 | |
| ONA AIRPARK | airport | United States | 38.44 | -82.20 | 572 | 0 | |
| ONAWA MUNI | airport | United States | 42.00 | -96.10 | 1047 | 0 | |
| ONB (Ononge Airport) | airport | -8.67 | 147.26 | 5800 | 0 | ||
| OND (ONDANGWA) | airport | Namibia | -17.88 | 15.95 | 3599 | 0 | |
| ONDANGWA | airport | Namibia | -17.88 | 15.95 | 3599 | 0 | |
| ONDWA | airport | India | 25.14 | 74.61 | 1450 | 0 | |
| ONE GRAND FIELD | airport | United States | 36.11 | -85.59 | 1000 | 0 | |
| ONE HOSPITAL TRUST | airport | United States | 41.83 | -71.41 | 406 | 0 | |
| ONE MERIDIAN PLAZA | airport | United States | 39.93 | -75.24 | 560 | 0 | |
| ONE O'CONNOR PLAZA-TOWER | airport | United States | 28.80 | -97.01 | 277 | 0 | |
| ONE OAK | airport | United States | 38.11 | -83.87 | 1000 | 0 | |
| ONE POLICE PLAZA | airport | United States | 40.71 | -74.00 | 244 | 0 | |
| ONE SIXTY FOUR PLACE | airport | United States | 33.12 | -98.23 | 1200 | 0 | |
| ONE TEN | airport | United States | 40.74 | -73.42 | 120 | 0 | |
| ONE ZERO EIGHT MILE AIRPORT | airport | Canada | 51.74 | -121.33 | 3127 | 0 | |
| ONEAL | airport | United States | 38.69 | -87.55 | 414 | 0 | |
| ONEIDA CITY HOSPITAL | airport | United States | 43.07 | -75.65 | 523 | 0 | |
| ONEIDA CO | airport | United States | 43.15 | -75.38 | 742 | 0 | |
| ONEONTA MUNI | airport | United States | 42.52 | -75.06 | 1764 | 0 | |
| ONG (MORNINGTON ISLAND) | airport | Australia | -16.66 | 139.18 | 33 | 0 | |
| ONH (ONEONTA MUNI) | airport | United States | 42.52 | -75.06 | 1764 | 0 | |
| ONI (Moanamani Airport) | airport | -3.98 | 136.08 | 5204 | 0 | ||
| ONIDA MUNI | airport | United States | 44.70 | -100.10 | 1874 | 0 | |
| ONION CREST AIRPARK | airport | United States | 40.77 | -99.15 | 2205 | 0 | |
| ONJ (ODATE NOSHIRO) | airport | Japan | 40.19 | 140.37 | 292 | 0 | |
| ONL (THE ONEILL MUNI JOHN L BAKER FLD) | airport | United States | 42.47 | -98.69 | 2031 | 0 | |
| ONLEY | airport | United States | 37.68 | -75.71 | 45 | 0 | |
| ONO (ONTARIO MUNI) | airport | United States | 44.02 | -117.01 | 2193 | 0 | |
| ONONDAGA COUNTY SHERIFF'S DEPARTMENT | airport | United States | 43.09 | -76.29 | 400 | 0 | |
| ONP (NEWPORT MUNI) | airport | United States | 44.58 | -124.06 | 160 | 0 | |
| ONQ (Zonguldak Airport) | airport | 41.51 | 32.09 | 39 | 0 | ||
| ONR (Monkira Airport) | airport | -24.82 | 140.53 | 107 | 0 | ||
| ONS (Onslow Airport) | airport | -21.67 | 115.11 | 7 | 0 | ||
| ONT (ONTARIO INTL) | airport | United States | 34.06 | -117.60 | 944 | 0 | |
| ONTARIO INTL | airport | United States | 34.06 | -117.60 | 944 | 0 | |
| ONTARIO MUNI | airport | United States | 44.02 | -117.01 | 2193 | 0 | |
| ONTONAGON CO SCHUSTER FLD | airport | United States | 46.85 | -89.37 | 669 | 0 | |
| ONU (Ono-i-Lau Airport) | airport | -20.66 | -178.74 | 110 | 0 | ||
| ONX (ENRIQUE ADOLFO JIMENEZ) | airport | Panama | 9.36 | -79.87 | 25 | 0 | |
| ONYON | airport | United States | 43.02 | -72.65 | 427 | 0 |