| 7501 | RPHX | National Car Co. | 1/1952-7/1954; eliminated 1/1956 | | NAKINA |
| 7502 | RPHX | National Car Co. | Jan-52 | | NRHS |
| 7503 | RPHX | NATIONAL CAR CO. | | | PWRC |
| 7504 | RPI | Paradise Air (Pvt) Ltd. | Callsign: Paradiseair, | CL | AVCODES |
| 7505 | RPIC | RAMPART PARTITIONS INC | | | SCAC4 |
| 7506 | RPID | RAPID TRANSPORT | | | SCAC4 |
| 7507 | RPIE | RAPID EXPRESS INC | | | SCAC3 |
| 7508 | RPII | R P I INC | | | SCAC3 |
| 7509 | RPIR | RAPID RUNNERS INC | | | SCAC3 |
| 7510 | RPIS | R P M INTERMODAL SERVICES INC | | | SCAC4 |
| 7511 | RPIT | RAPID TRANSPORT (DIV OF ODFL) | | | SCAC3 |
| 7512 | RPIW | REDRIVEN POWER INC | | | SCAC4 |
| 7513 | RPIX | Rhone-Poulenc Inc. | added 1/1987; 1/1994; eliminated 1/1996; 7/2000-7/2005 (not listed) | | NAKINA |
| 7514 | RPIX | Rhone-Poulenc Inc. | added 1/87; 1/94; eliminated 1/96; 7/2000 | | NRHS |
| 7515 | RPIX | RHONE-POULENC INC. | | | PWRC |
| 7516 | RPIX | Rhone-Poulenc | | | RSRV |
| 7517 | RPIX | RHONE-POULENC INCORPORATED | | | SCAC4 |
| 7518 | RPIY | RUSSELL PLYWOOD INC | | | SCAC4 |
| 7519 | RPIZ | ROPER PUMP, INC. | | | PWRC |
| 7520 | RPJD | REMCAN PROJECTS LTD | | | SCAC4 |
| 7521 | RPJL | ROMERO PADILLA, JUAN LUIS | | | SCAC4 |
| 7522 | RPJM | RAPP, J M LLC | | | SCAC4 |
| 7523 | RPJS | ROBINSON, P & J & SON | | | SCAC3 |
| 7524 | RPJS | RADOCHA, PETER J & SONS INC | | | SCAC4 |
| 7525 | RPJT | ROSSI, PETE J | | | SCAC3 |
| 7526 | RPK | M/S Royal Airlines (PVT) Limited | IATA: R0, Callsign: Royal Pakistan, | PK | AVCODES |
| 7527 | RPK | Royal Airlines | IATA: R0 | | ICAO1 |
| 7528 | RPKD | RUSH PACKAGE DELIVERY INC | | | SCAC3 |
| 7529 | RPKD | RUSH TRANSPORTATION/LOGISTICS INC | | | SCAC4 |
| 7530 | RPKE | RIPPENTROP, KURT EXPRESS | | | SCAC4 |
| 7531 | RPKG | R & P TRUCKING | | | SCAC4 |
| 7532 | RPKI | RUPUNUNI TRUCKING INC | | | SCAC4 |
| 7533 | RPKT | RAPPAHANNOCK TRACTOR CO | | | SCAC4 |
| 7534 | RPL | Rompetrol Logistics SA | | CZ | VKM |
| 7535 | RPLA | RPL ASSOCIATES INC | | | SCAC4 |
| 7536 | RPLB | RIVER PLACE LOGISTICS INC | | | SCAC4 |
| 7537 | RPLC | REPUBLIC PORTSMOUTH STORAGE CORPORA | | | SCAC3 |
| 7538 | RPLC | RUBY PALLETS LLC | | | SCAC4 |
| 7539 | RPLD | RECON PETROTECHNOLOGIES LTD | | | SCAC4 |
| 7540 | RPLI | RUN'N P LLC | | | SCAC4 |
| 7541 | RPLM | RUSH PETROLEUM TRANSPORT INC | | | SCAC3 |
| 7542 | RPLN | ROLLING PLAINS TRANSPORT INC | | | SCAC3 |
| 7543 | RPLO | RICKS PRODUCE LLC | | | SCAC4 |
| 7544 | RPLP | R P LOGISTICS INC | | | SCAC4 |
| 7545 | RPLQ | RAMBOS PRODUCE LLC | | | SCAC4 |
| 7546 | RPLW | REPUBLIC VAN & STORAGE OF LOS ANGEL | | | SCAC3 |
| 7547 | RPM | Polaris Aviation Solutions | Callsign: Cobalt, | USA | AVCODES |
| 7548 | RPM | rail Promotion | | DE | VKM |
| 7549 | RPMA | RPM TRANSPORT INC | | | SCAC4 |
| 7550 | RPMB | RPM | | | SCAC4 |
| 7551 | RPMC | RPM COURIER SYSTEMS INC | | | SCAC4 |
| 7552 | RPME | RPM EXPRESS LTD | | | SCAC4 |
| 7553 | RPMF | RAPID MOTOR FREIGHT INC | | | SCAC3 |
| 7554 | RPMH | R P M TRANSPORTATION (HAWAII) INC | | | SCAC4 |
| 7555 | RPMI | RPM TRANSPORTATION, INC | | | SCAC3 |
| 7556 | RPMI | RPM TRANSPORTATION INC | | | SCAC4 |
| 7557 | RPMJ | RPM OF JACKSONVILLE INC | | | SCAC3 |
| 7558 | RPMK | RPM TRUCKING CO LTD | | | SCAC3 |
| 7559 | RPML | RPM LOGISTICS INC | | | SCAC4 |
| 7560 | RPMM | RPM COURIER SERVICE INC | | | SCAC3 |
| 7561 | RPMM | RICHARD, PAUL MODULAR & MINI HOME M | | | SCAC4 |
| 7562 | RPMN | RPM INTERMODAL TRANSPORT INC | | | SCAC3 |
| 7563 | RPMN | R P M TRANSPORTATION | | | SCAC4 |
| 7564 | RPMO | R P M FREIGHTWAYS INC | | | SCAC3 |
| 7565 | RPMQ | R P M LOGISTICS INC | | | SCAC4 |
| 7566 | RPMR | R P M TRUCKING | | | SCAC3 |
| 7567 | RPMR | R P M TRANSPORT | | | SCAC4 |
| 7568 | RPMS | REYNOLDS PAPER MILL SUPPLY CORP | | | SCAC3 |
| 7569 | RPMS | RPM LEASING CORP | | | SCAC4 |
| 7570 | RPMT | RPM TRUCKING & HOTSHOT INC | | | SCAC3 |
| 7571 | RPMT | RPM TRANSPORTATION COMPANY | | | SCAC4 |
| 7572 | RPMU | RIO PUELO SPA | | RCH | BIC |
| 7573 | RPMW | READS-PERKI | | | SCAC4 |
| 7574 | RPMX | RPMG, INC. | | | PWRC |
| 7575 | RPMX | RPMG INC | | | SCAC4 |
| 7576 | RPMY | R P M TRUCKING INC | | | SCAC3 |
| 7577 | RPMZ | (REAZ) TRANSAMERICA LEASING, INC. | | | PWRC |
| 7578 | RPMZ | TAL International | | | RSRV |
| 7579 | RPN | US Immigration and Custom Enforcement | Callsign: Repatriate, | USA | AVCODES |
| 7580 | RPND | RAPID PARCEL POST AND DELIVERY | | | SCAC3 |
| 7581 | RPNJ | R I PAGE & JONES INC | | | SCAC3 |
| 7582 | RPNR | ROOP & ROOP TRUCKING | | | SCAC3 |
| 7583 | RPNR | ROUNDUP PROPANE CO | | | SCAC4 |
| 7584 | RPNS | ROARK, PAUL & SONS | | | SCAC3 |
| 7585 | RPNX | Rhodia Inc. (RPNX) | added 4/2008; added 7/2009 | | NAKINA |
| 7586 | RPNX | RHODIA, INC. | | | PWRC |
| 7587 | RPNX | RHODIA INC | | | SCAC4 |
| 7588 | RPO | Aeroposta, S.A. | Callsign: Aeroposta, | RA | AVCODES |
| 7589 | RPOH | RPTS INC | | | SCAC3 |
| 7590 | RPOH | RPTS INC | | | SCAC4 |
| 7591 | RPOOL | RailPool GmbH | | D | TRAFFIC |
| 7592 | RPOOL | Railpool GmbH | | DE | VKM |
| 7593 | RPOP | RAMP OPERATION INC | | | SCAC3 |
| 7594 | RPOST | Deutsche Reichspost | | D | TRAFFIC |
| 7595 | RPOX | Refinery Products Co., Division of QuVoe Chemical Industries, Inc. | added 4/1967; 4/1970; eliminated 7/1970 | | NAKINA |
| 7596 | RPOX | Refinery Products Co. | added 10/1962; 7/1965-10/1966; eliminated 4/1967 | | NAKINA |
| 7597 | RPOX | Refinery Products Co. | 7/65-10/66; eliminated 4/67 | | NRHS |
| 7598 | RPOX | Refinery Products Co., Division of QuVoe Chemical Industries, Inc. | added 4/67; 4/70; eliminated 7/70 | | NRHS |
| 7599 | RPOX | REFINERY PRODUCTS CO., DIV. QUVOE CHEMICAL INDUSTRIES, INC. | | | PWRC |
| 7600 | RPOX | REFINERY PRODUCTS CO | | | SCAC3 |
