| 401 | RTMX | General Electric Rail Services Corp. | added 1/2000; 7/2000 | | NRHS |
| 402 | RTMX | (NATX) GENERAL ELECTRIC RAIL SERVICES CORP. [RICHMOND LEASING CO.; MARATHON LEASING CO.] | | | PWRC |
| 403 | RTMX | Richmond Leasing | | | RSRV |
| 404 | RTMX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 405 | RTMY | RTM LINES | | | SCAC4 |
| 406 | RTMZ | (REAZ) TRANSAMERICA LEASING, INC. | | | PWRC |
| 407 | RTMZ | TIP Intermodal Services | | | RSRV |
| 408 | RTMZ | TRANSPORT INTERNATIONAL POOL INC | | | SCAC4 |
| 409 | RTN | Raytheon Aircraft Company | Callsign: Raytheon, | USA | AVCODES |
| 410 | RTN | Raytheon Aircraft Company | | | ICAO1 |
| 411 | RTNA | REMICK TRANS AMERICA INC | | | SCAC3 |
| 412 | RTNB | ROTTER TRUCKING | | | SCAC3 |
| 413 | RTNB | RTRANS | | | SCAC4 |
| 414 | RTND | REILES TRANSFER & DELIVERY INC | | | SCAC3 |
| 415 | RTND | REED TRADING LTD | | | SCAC4 |
| 416 | RTNF | RITE WAY TRANSFER INC | | | SCAC3 |
| 417 | RTNG | REED TRUCKING | | | SCAC3 |
| 418 | RTNJ | RTS TRANSPORTATION LLC | | | SCAC4 |
| 419 | RTNL | RAM TRANSPORTATION AND LEASING | | | SCAC3 |
| 420 | RTNM | RTC TRANSPORT LLC | | | SCAC4 |
| 421 | RTNN | ROYAL TRANSPORT INC | | | SCAC3 |
| 422 | RTNN | RONTRANS INTERNATIONAL | | | SCAC4 |
| 423 | RTNO | REITANO TRUCKING | | | SCAC3 |
| 424 | RTNO | RT TRANSPORT | | | SCAC4 |
| 425 | RTNP | RATE TRANSPORT CO INC | | | SCAC3 |
| 426 | RTNQ | R & T TRANSPORTATION INC | | | SCAC4 |
| 427 | RTNR | ROCK THEN ROLL INC | | | SCAC3 |
| 428 | RTNS | RELIABLE TRANSFER & STORAGE COMPANY | | | SCAC3 |
| 429 | RTNT | ROMANS 10:9 TOURS INCORPORATED | | | SCAC3 |
| 430 | RTNY | ROCHA, TONY N JR | | | SCAC3 |
| 431 | RTO | Arhabaev Tourism Airlines | Callsign: Artoair, | KZ | AVCODES |
| 432 | RTO | Rectimo Air Transports SAS | Callsign: Raccoon, | F | AVCODES |
| 433 | RTO | Arhabaev Tourism Airlines | | | ICAO1 |
| 434 | RTO | Rio Tinto Group | Mining company | AUS | TRAFFIC |
| 435 | RTOA | RESOURCE TRANSPORTATION OF AMERICA | | | SCAC3 |
| 436 | RTOB | RICHS TOURS | | | SCAC3 |
| 437 | RTOC | RUTH OIL COMPANY | | | SCAC4 |
| 438 | RTOD | | Real: RTO, City: Dijon | F | TRAFFIC |
| 439 | RTOG | Regionstog A/S | 2009 - | DK | jernbanen.dk |
| 440 | RTOG | Regionstog A/S | 2009 | DK | TRAFFIC |
| 441 | RTOG | Regionstog A/S | | DK | VKM |
| 442 | RTOH | R B TRANSPORTATION | | | SCAC3 |
| 443 | RTOI | RAM TRANSPORTATION INC | | | SCAC3 |
| 444 | RTOI | RMA TRANSPORTATION SERVICES INC | | | SCAC4 |
| 445 | RTOL | ROYAL TRANSPORT LTD | | | SCAC3 |
| 446 | RTOL | ROAD TRANSPORTATION SOLUTIONS | | | SCAC4 |
| 447 | RTON | RACER TRANSPORTATION INC | | | SCAC3 |
| 448 | RTON | ROUTE ONE TRANSPORT | | | SCAC4 |
| 449 | RTOO | RAJASON TOOLS INC | | | SCAC4 |
| 450 | RTOP | RED TOP CABS INC | | | SCAC3 |
| 451 | RTOQ | RILEYS TRANSPORTATION OF OHIO INC | | | SCAC4 |
| 452 | RTOS | R TRANSPORT SERVICES LLC | | | SCAC4 |
| 453 | RTOW | RUBENS TOWING | | | SCAC4 |
| 454 | RTOZ | (REAZ) RETIRED 04-06-93 ATP (ACI 2490) | | | PWRC |
| 455 | RTPF | ROUTED THRU-PAC INC | | | SCAC3 |
| 456 | RTPF | ROUND TOP FARM | | | SCAC4 |
| 457 | RTPG | ROUND TRIP TRANSPORT LLC | | | SCAC4 |
| 458 | RTPI | ROUTH TRANSPORTATION | | | SCAC3 |
| 459 | RTPI | ROUTH TRANSPORTATION | | | SCAC4 |
| 460 | RTPJ | RST TRANSPORT INC | | | SCAC3 |
| 461 | RTPK | R & T PRODUCTS INC | | | SCAC4 |
| 462 | RTPL | REGAL TENT PRODUCTIONS LTD | | | SCAC4 |
| 463 | RTPM | RANGER TRANSPORT INC | | | SCAC3 |
| 464 | RTPM | RANGER TRANSPORT INC | | | SCAC4 |
| 465 | RTPN | ROBERTS TRANSPORTATION | | | SCAC3 |
| 466 | RTPO | RELIANCE TRANSPORT CO | | | SCAC3 |
| 467 | RTPP | RAPID TRANSPORT CORPORATION | | | SCAC3 |
| 468 | RTPR | REAL TRANSPORTATION | | | SCAC3 |
| 469 | RTPR | RT EXPRESS LLC | | | SCAC4 |
| 470 | RTPS | REDMOND TRANSPORTATION SYSTEMS | | | SCAC3 |
| 471 | RTPS | ROUSE TRANSPORT LLC | | | SCAC4 |
| 472 | RTPT | RIC TRANSPORT S.A | | | SCAC3 |
| 473 | RTPV | ROCHES TRANSPORTING INC | | | SCAC3 |
| 474 | RTPX | General Electric Railcar Corp. | added 4/2004; 7/2005 | | NAKINA |
| 475 | RTPX | Savage-Tolk Energy Services | added 4/2001; eliminated 4/2004 | | NAKINA |
| 476 | RTPX | Wheelabrator Coal Services Co. | added 4/1982; 1/1994-7/2000; eliminated 4/2001 | | NAKINA |
| 477 | RTPX | Wheelabrator Coal Services Co. | added 4/82; 1/94-7/2000; eliminated 4/2001 | | NRHS |
| 478 | RTPX | Savage-Tolk Energy Services | added 4/2001 | | NRHS |
| 479 | RTPX | *SAVAGE-TOLK ENERGY SERVICES [(WCSX) WHEELABRATOR COAL SERVICES CO.] | | | PWRC |
| 480 | RTPX | +GENERAL ELECTRIC RAIL SERVICES CORP. | | | PWRC |
| 481 | RTPX | Wheelabrator Coal Services (GE Rail Services) | | | RSRV |
| 482 | RTPX | GENERAL ELECTRIC RAILCAR SERVICES C | | | SCAC4 |
| 483 | RTQ | Air Turquoise SAS | IATA: RT, Ceased operations on 02 August 2006. | F | AVCODES |
| 484 | RTQ | Air Turquoise | | | ICAO1 |
| 485 | RTQA | RT2000 CARTAGE | | | SCAC4 |
| 486 | RTQI | R.T.Q. INC. | | | SCAC4 |
| 487 | RTQL | RELIABLE TRANSPORT (QUEBEC) INC | | | SCAC3 |
| 488 | RTQS | ROBART TRUCKING SERVICE INC | | | SCAC3 |
| 489 | RTR | Sociedade Brasileira de Turismo (ROTASTUR) | IATA: DR, Callsign: Delta Romeo, ICAO callsign changed to Rotatur | BR | AVCODES |
| 490 | RTR | Air Trust JSC | Callsign: Air Trust, Founded Aug 2012. | KZ | AVCODES |
| 491 | RTR | Sociedade Brasileira de Turismo (ROTASTUR) | Callsign: Rotatur, ICAO callsign changed from Delta Romeo | BR | AVCODES |
| 492 | RTR | Rotatur | | | ICAO1 |
| 493 | RTRA | R AND D TRANSPORTATION | | | SCAC3 |
| 494 | RTRA | REINHARD TRANSPORTATION LLC | | | SCAC4 |
| 495 | RTRAN | RailTrans | | A | TRAFFIC |
| 496 | RTRB | ROSE TRUCK BROKERS INC | | | SCAC3 |
| 497 | RTRC | RICHMOND TERMINAL RAILWAY CO. | | | PWRC |
| 498 | RTRC | REED TRUCKING COMPANY INC | | | SCAC3 |
| 499 | RTRH | R T R TRUCKING INC | | | SCAC3 |
| 500 | RTRI | ROCOR TRUCK LINES INC | | | SCAC3 |
