| 1 | RTO | Arhabaev Tourism Airlines | Callsign: Artoair, | KZ | AVCODES |
| 2 | RTO | Rectimo Air Transports SAS | Callsign: Raccoon, | F | AVCODES |
| 3 | RTO | Arhabaev Tourism Airlines | | | ICAO1 |
| 4 | RTO | Rio Tinto Group | Mining company | AUS | TRAFFIC |
| 5 | RTOA | RESOURCE TRANSPORTATION OF AMERICA | | | SCAC3 |
| 6 | RTOB | RICHS TOURS | | | SCAC3 |
| 7 | RTOC | RUTH OIL COMPANY | | | SCAC4 |
| 8 | RTOD | | Real: RTO, City: Dijon | F | TRAFFIC |
| 9 | RTOG | Regionstog A/S | 2009 - | DK | jernbanen.dk |
| 10 | RTOG | Regionstog A/S | 2009 | DK | TRAFFIC |
| 11 | RTOG | Regionstog A/S | | DK | VKM |
| 12 | RTOH | R B TRANSPORTATION | | | SCAC3 |
| 13 | RTOI | RAM TRANSPORTATION INC | | | SCAC3 |
| 14 | RTOI | RMA TRANSPORTATION SERVICES INC | | | SCAC4 |
| 15 | RTOL | ROYAL TRANSPORT LTD | | | SCAC3 |
| 16 | RTOL | ROAD TRANSPORTATION SOLUTIONS | | | SCAC4 |
| 17 | RTON | RACER TRANSPORTATION INC | | | SCAC3 |
| 18 | RTON | ROUTE ONE TRANSPORT | | | SCAC4 |
| 19 | RTOO | RAJASON TOOLS INC | | | SCAC4 |
| 20 | RTOP | RED TOP CABS INC | | | SCAC3 |
| 21 | RTOQ | RILEYS TRANSPORTATION OF OHIO INC | | | SCAC4 |
| 22 | RTOS | R TRANSPORT SERVICES LLC | | | SCAC4 |
| 23 | RTOW | RUBENS TOWING | | | SCAC4 |
| 24 | RTOZ | (REAZ) RETIRED 04-06-93 ATP (ACI 2490) | | | PWRC |
