| 1 | RGO | Argo, S.A. | Callsign: Argos, founded in 1971. Ceased operations during 1987. | DOM | AVCODES |
| 2 | RGO | Regional Linhas Aeréas Ltda | Callsign: Passaro, | BR | AVCODES |
| 3 | RGO | Argo | | | ICAO1 |
| 4 | RGOC | REGAL OIL COMPANY INC | | | SCAC4 |
| 5 | RGOL | REGIONAL ASSOCIATES INC | | | SCAC4 |
| 6 | RGOM | ROGOVIN MOVING & STORAGE CO INC | | | SCAC3 |
| 7 | RGOP | RIO GRANDE OIL COMPANY | | | SCAC4 |
| 8 | RGOT | RESTIGOUCHE TRANSPORT LIMITED | | | SCAC4 |
| 9 | RGOX | Richfield Oil Corp. | 7/1937-4/1938 | | NAKINA |
| 10 | RGOX | Rio Grande Oil Co. | 8/1920-7/1935 | | NAKINA |
| 11 | RGOX | Richfield Oil Co. of California (Richfield Oil Corp.) | Apr-38 | | NRHS |
| 12 | RGOX | *RICHFIELD OIL CORP. [RIO GRANDE OIL CO.] | | | PWRC |
| 13 | RGOX | *RAILGON COMPANY | | | PWRC |
| 14 | RGOX | TTX COMPANY | | | SCAC4 |
