| 501 | RSS | Rossair (Pty) Ltd. | Callsign: Ross Charter, | ZA | AVCODES |
| 502 | RSS | Rossair | | | ICAO1 |
| 503 | RSS | Rockdale, Sandow & Southern R.R. Co. | 1/1975-1/1980; added 7/1980; 1/1994-7/2005 | | NAKINA |
| 504 | RSS | Rockdale, Sandow & Southern R.R. Co. | 1/75-1/80; added 7/80; 1/94-7/2000 | | NRHS |
| 505 | RSS | *ROCHESTER SUBWAY | | | PWRC |
| 506 | RSS | +ROCKDALE, SANDOW & SOUTHERN RAILROAD CO. | | | PWRC |
| 507 | RSS | Rochester Subway (Rockdale, Sandow and Southern Railroad) | | | RSRV |
| 508 | RSSA | ROADMASTER TRANSPORTATION, INC. | | | SCAC3 |
| 509 | RSSA | ROADMASTER TRANSPORTATION INC | | | SCAC4 |
| 510 | RSSB | ROSS BROTHERS | | | SCAC3 |
| 511 | RSSC | ROSSI CARTAGE INC | | | SCAC3 |
| 512 | RSSC | REGENT SEVEN SEAS CRUISES INC | | | SCAC4 |
| 513 | RSSE | ROSSI CORPORATION | | | SCAC4 |
| 514 | RSSF | RUSSELL FARMS | | | SCAC3 |
| 515 | RSSH | ROSARIO SHIPPING AND TRADING S.A. | | | SCAC3 |
| 516 | RSSH | RILEY-SHERMA | | | SCAC4 |
| 517 | RSSI | ROSES STORES NC | | | SCAC3 |
| 518 | RSSJ | RTJ SPECIALIZED SERVICES | | | SCAC4 |
| 519 | RSSK | ROSS, KENNETH TRUCKING | | | SCAC3 |
| 520 | RSSK | RAMOS SEVEN SEVEN SEVEN (777) TRUCK | | | SCAC4 |
| 521 | RSSL | ROSSEE OIL CO INC | | | SCAC4 |
| 522 | RSSM | ROSS STEEL & TRANSPORTATION INC | | | SCAC3 |
| 523 | RSSN | ROUSSEAU METAL INC | | | SCAC4 |
| 524 | RSSO | R & S STORES INC, | | | SCAC3 |
| 525 | RSSP | REDDING SEED AND SUPPLY INC | | | SCAC3 |
| 526 | RSSQ | RS SHIPPING SRL | | | SCAC4 |
| 527 | RSSR | ROSSI TRANSPORTATION COMPANY | | | SCAC3 |
| 528 | RSSR | RESSLER, ROY & SON INC | | | SCAC4 |
| 529 | RSSS | ROSSMANN SHIPPING SERVICES | | | SCAC3 |
| 530 | RSST | ROSS TRUCKING COMPANY | | | SCAC3 |
| 531 | RSSU | ROYAL WOLF TRADING AUSTRALIA PTY LTD | | AUS | BIC |
| 532 | RSSU | ROYAL WOLF TRADING AUSTRALIA PTY LT | | | SCAC4 |
| 533 | RSSV | RUMFORD SHUTTLE SERVICE | | | SCAC3 |
| 534 | RSSW | RAY SEA SA | | | SCAC4 |
| 535 | RSSX | Railserve, Inc. | 7/2005 (not listed) | | NAKINA |
| 536 | RSSX | *RAIL SWITCHING SERVICE, INC. | | | PWRC |
| 537 | RSSX | +RAILSERVE, INC. | | | PWRC |
| 538 | RSSX | Railserve Inc. | | | RSRV |
| 539 | RSSX | RAILSERVE INC | | | SCAC4 |
| 540 | RSSY | RGL SPECIALTY SERVICES LLC | | | SCAC4 |
| 541 | RST | Resort Air | Callsign: Resort Air, | USA | AVCODES |
| 542 | RST | Resort Air | | | ICAO1 |
| 543 | RST | Rangier-, Servce- und Transportgesellschaft mbH | St. Ingbert | D | privat-bahn.de |
| 544 | RSTA | ROSSI TRANSPORT SERVICE, INC. | | | SCAC3 |
| 545 | RSTB | R & S TRUCKING | | | SCAC3 |
| 546 | RSTB | RST | | | SCAC4 |
| 547 | RSTC | ROSE TRUCKING INCORPORATED | | | SCAC3 |
| 548 | RSTD | RST INDUSTRIES LTD | | | SCAC3 |
| 549 | RSTE | RICE STREET TOWING INC | | | SCAC3 |
| 550 | RSTE | RED STAR FUELS | | | SCAC4 |
| 551 | RSTF | REIS TRUCKING INC | | | SCAC3 |
| 552 | RSTF | REIS TRUCKING INC | | | SCAC4 |
| 553 | RSTG | R & S TRUCKING INC | | | SCAC3 |
| 554 | RSTG | R & S TRUCKING | | | SCAC4 |
| 555 | RSTH | ROSE TRANSPORTATION CO | | | SCAC3 |
| 556 | RSTI | R S TRUCKING CO | | | SCAC3 |
| 557 | RSTI | RISING STAR TRANSPORTATION INC | | | SCAC4 |
| 558 | RSTJ | R & S TRUCKING | | | SCAC3 |
| 559 | RSTK | REESE TRUCKING | | | SCAC4 |
| 560 | RSTK | Rolling Stock Company | | RO | TRAFFIC |
| 561 | RSTL | R S TRAILER REPAIR INC | | | SCAC3 |
| 562 | RSTL | RST INDUSTRIES LIMITED | | | SCAC4 |
| 563 | RSTM | R & S TRANSPORTERS INTERMODAL SERVI | | | SCAC4 |
| 564 | RSTN | REASNOR & SON TRUCKING | | | SCAC3 |
| 565 | RSTN | R & S TRUCKING | | | SCAC4 |
| 566 | RSTO | RELIABLE-SCOTT TRANSPORT LIMITED | | | SCAC3 |
| 567 | RSTP | RELIABLE SOUTHERN TRANSPORT INC | | | SCAC4 |
| 568 | RSTQ | RISS TRANSPORTATION CO | | | SCAC3 |
| 569 | RSTQ | ROSE, STEVE | | | SCAC4 |
| 570 | RSTR | R & S TRANSPORT | | | SCAC3 |
| 571 | RSTR | R M S TRANSPORT LLC | | | SCAC4 |
| 572 | RSTS | Ruhr-Stickstoff AG | | D | TRAFFIC |
| 573 | RSTU | UNIT45 BV | | NL | BIC |
| 574 | RSTU | UNIT 45 BV | | | SCAC4 |
| 575 | RStV | Rinteln - Stadthagener Verkehrs GmbH | Celle | D | privat-bahn.de |
| 576 | RSTV | R AND S TRUCKING INC (NC CORP) | | | SCAC3 |
| 577 | RSTV | Rinteln-Stadthagener Verkehrsbetriebe | | D | TRAFFIC |
| 578 | RSTV | Rinteln-Stadthagener Verkehrs GmbH | | DE | VKM |
| 579 | RSTW | ROTTERDAM SHIPPING & TRADING B V | | | SCAC4 |
| 580 | RSTX | RSTX Inc. | added 1/1972; 1/1975-1/1980; eliminated 10/1985; added 1/1986; eliminated 10/1988 | | NAKINA |
| 581 | RSTX | RSP Motor Transport Co. | added 4/1969; 4/1970; eliminated 1/1972 | | NAKINA |
| 582 | RSTX | RSP Motor Transport Co. | added 4/69; 4/70; eliminated 1/72 | | NRHS |
| 583 | RSTX | RSTX Inc. | added 1/72; 1/75-1/80; added 1/86; eliminated 10/88 | | NRHS |
| 584 | RSTX | RSTX INC. [RSP MOTOR TRANSPORT CO.] | | | PWRC |
| 585 | RSTX | RSTX Inc. | | | RSRV |
| 586 | RSU | Compania Boliviana de Transporte Aereo Privado Aerosur, S.A. | IATA: 5L, Callsign: Asur, IATA Prefix: 275, Founded in 1992. Ceased operations on 17 May 2012. AOC revoked on 20 July 2012. | BOL | AVCODES |
| 587 | RSU | Aerosur | IATA: 5L | | ICAO1 |
| 588 | RSU | Compania Boliviana de Transporte Aereo Privado Aerosur, S.A. | | BOL | TRAFFIC |
| 589 | RSU | RailSupport | | DE | VKM |
| 590 | RSUS | ROSEN USA | | | SCAC4 |
| 591 | RSUT | ROSENAU TRANSPORT LTD | | | SCAC4 |
| 592 | RSUX | Riley Stoker Corp. | added 1/1968; 4/1970-1/1994; eliminated 7/1998; 7/2000-7/2005 (not listed) | | NAKINA |
| 593 | RSUX | Riley Stoker Corp. | added 1/68; 4/70-1/94; eliminated 7/98; 7/2000 | | NRHS |
| 594 | RSUX | RILEY STOKER CORP. | | | PWRC |
| 595 | RSUX | Riley Stoker Corporation | | | RSRV |
| 596 | RSUX | RILEY STOKER CORP. | | | SCAC4 |
| 597 | RSV | Air Services | Callsign: Sernou, | F | AVCODES |
| 598 | RSV | Red Sky Ventures CC | Callsign: Red Sky, | NAM | AVCODES |
| 599 | RSV | Red Sky Ventures | | | ICAO1 |
| 600 | RSV | Reutlinger Stadtverkehrsgesellschaft mbH | | D | TRAFFIC |
