| 1 | RO | Compnia Nationala de Transporturi Aeriene Romane TAROM S.A. | ICAO: ROT, Callsign: Tarom, IATA Prefix: 281, Name changed from TAROM - Romanian Air Transport. | RO | AVCODES |
| 2 | ROA | Reno Air, Inc. | IATA: QQ, Callsign: Reno Air, Merged in American Airlines | USA | AVCODES |
| 3 | ROA | Roland Air Flugverkehrs und Vertriebsgesellschaft mbH | IATA: DU, Callsign: Roland Air, | D | AVCODES |
| 4 | ROA | Atom Airways | Callsign: Atomways, | RO | AVCODES |
| 5 | ROA | Reno Air | IATA: QQ | | ICAO1 |
| 6 | ROAA | ROADEX SERVICES LTD | | | SCAC4 |
| 7 | ROAB | ROBBINS, ALLAN B | | | SCAC3 |
| 8 | ROAB | ROGERS FARM SUPPLY | | | SCAC4 |
| 9 | ROAC | Romanian Air Corps | Real: RAC, The Romanian Air Corps or Aviation Corps (RAC) (Romanian: Corpul de Aviație) was the air arm of the Romanian army until the formation of the Romanian Air Force in 1924 | RO | TRAFFIC |
| 10 | ROAD | ROAD COMMERCE CORPORATION | | | PWRC |
| 11 | ROAD | ROAD COMMERCE CORPORATION | | | SCAC3 |
| 12 | ROAD | ROAD LINK XPRESS | | | SCAC4 |
| 13 | ROADR | Roadrunner | City: Harlow | GB | TRAFFIC |
| 14 | ROAE | ROSS, A J LOGISTICS INC | | | SCAC3 |
| 15 | ROAE | ROAD RUNNER TRUCKING | | | SCAC4 |
| 16 | ROAF | ROAD AMERICAN FREIGHT SYSTEMS INC | | | SCAC3 |
| 17 | ROAF | Romanian Air Force | | RO | TRAFFIC |
| 18 | ROAG | ROWLAND, LONNIE TRUCKING | | | SCAC3 |
| 19 | ROAJ | ROADAIR LEASING INC | | | SCAC3 |
| 20 | ROAK | ROADKINS TRUCKING CORP | | | SCAC3 |
| 21 | ROAL | ROANE TRANSPORTATION SERVICES LLC | | | SCAC4 |
| 22 | ROAM | ROADMAS | | | SCAC4 |
| 23 | ROAN | ROANS TRUCKING SERVICE | | | SCAC3 |
| 24 | ROAN | ROANE LOGISTICS INC | | | SCAC4 |
| 25 | ROAO | ROARING EXPRESS CO INC | | | SCAC3 |
| 26 | ROAO | ROBERT FILM SERVICES INC | | | SCAC4 |
| 27 | ROAP | ROAP TRANSPORT INC | | | SCAC3 |
| 28 | ROAQ | ROAYL TRUCKING CO | | | SCAC3 |
| 29 | ROAR | ROAD AND RAIL TRUCKING COMPANY | | | PWRC |
| 30 | ROAR | ROAR LOGISTICS INC | | | SCAC4 |
| 31 | ROAT | ROES STAIR CO | | | SCAC4 |
| 32 | ROAU | ROAM GLOBAL SOLUTIONS LLC | | USA | BIC |
| 33 | ROAW | ROBINSON AND WILLIAMS TRANSPORT INC | | | SCAC3 |
| 34 | ROAY | ROAD-CON SYSTEMS INC | | | SCAC3 |
| 35 | ROB | African Inter. Airways (West Africa) Ltd. | Callsign: Higher Ground, | WAN | AVCODES |
| 36 | ROB | SLL Resources Limited | Callsign: Bat Jet, | RSM | AVCODES |
| 37 | ROB | Robel | | DE | VKM |
| 38 | ROBA | ROBINSONS EXPRESS CO, INC | | | SCAC3 |
| 39 | ROBA | ROBERTS ASSOCIATES INC | | | SCAC4 |
| 40 | ROBB | ROBISON TRUCKING INC | | | SCAC4 |
| 41 | ROBC | ROBINSON CARTAGE CO | | | SCAC3 |
| 42 | ROBC | ROBINSON CARTAGE COMPANY | | | SCAC4 |
| 43 | ROBD | ROBIDEAUS EXPRESS, INC | | | SCAC3 |
| 44 | ROBD | RINGER OIL OF PA INC | | | SCAC4 |
| 45 | ROBE | ROBERTS TRUCKING CO, INC | | | SCAC3 |
| 46 | ROBE | ROBEY, JEFF TRUCK LINES INC | | | SCAC4 |
| 47 | ROBF | ROBINSON FREIGHT LINES, INC, THE | | | SCAC3 |
| 48 | ROBG | ROBERTS, GEORGE F | | | SCAC3 |
| 49 | ROBH | ROBART TRANSPORTATION INC | | | SCAC3 |
| 50 | ROBH | ROBART TRANSPORTATION INC | | | SCAC4 |
| 51 | ROBI | ROBIN TRUCK LINE | | | SCAC3 |
| 52 | ROBI | ROBIN TRUCK LINE | | | SCAC4 |
| 53 | ROBK | ROBERTS, TOM M | | | SCAC3 |
| 54 | ROBK | ROBERTS, TOM M TRUCKLINES INC | | | SCAC4 |
| 55 | ROBL | ROBERTS TRUCKING | | | SCAC3 |
| 56 | ROBL | ROBELLO TRANSPORTATION | | | SCAC4 |
| 57 | ROBM | ROBINSON TRANSPORTATION INC | | | SCAC3 |
| 58 | ROBM | ROBINSON TRANSPORTATION INC | | | SCAC4 |
| 59 | ROBN | ROBSON CO INC | | | SCAC3 |
| 60 | ROBN | ROBUST TRANSPORT SERVICES LTD | | | SCAC4 |
| 61 | ROBO | ROBEY CARTAGE COMPANY INC | | | SCAC3 |
| 62 | ROBP | ROBERTSON ENTERPRIZE INC | | | SCAC4 |
| 63 | ROBQ | ROBINSON, J AND B CARTAGE CO | | | SCAC3 |
| 64 | ROBR | ROBBINS, ROBERTA | | | SCAC3 |
| 65 | ROBS | ROBINSON TRUCKING | | | SCAC4 |
| 66 | ROBU | ROBERTO BUCCI S.P.A | | I | BIC |
| 67 | ROBV | ROBINSON STAVE INC | | | SCAC4 |
| 68 | ROBW | ROBINSON, W T & SON TRUCKING CONTRA | | | SCAC3 |
| 69 | ROBY | ROUSES BODY SHOP INC | | | SCAC3 |
| 70 | ROBZ | ROBCO TRANSPORTATION, INC. | | | PWRC |
| 71 | ROBZ | Robco Transportation | | | RSRV |
| 72 | ROBZ | ROBCO TRANSPORTATION, INC. | | | SCAC4 |
| 73 | ROC | Rocky Mountain Airlines | | CDN | AVCODES |
| 74 | ROC | Rocky Mountain Airlines | | | ICAO1 |
| 75 | ROCA | R O C TRANSPORT INC | | | SCAC4 |
| 76 | ROCA | Republic of China Army | | RC | TRAFFIC |
| 77 | ROCAF | Republic of China Air Force | | ROC | TRAFFIC |
| 78 | ROCB | ROSALES OIL COMPANY | | | SCAC4 |
| 79 | ROCD | ROCHESTER CITY DELIVERY INC | | | SCAC3 |
| 80 | ROCD | ROCHESTER CITY DELIVERY INC | | | SCAC4 |
| 81 | ROCF | ROBBINS FARMS | | | SCAC4 |
| 82 | ROCH | ROWAYTON FUEL & OIL CO INC | | | SCAC4 |
| 83 | ROCI | RANCHERS OIL CO | | | SCAC3 |
| 84 | ROCJ | ROCHE MOVING & STORAGE INC | | | SCAC3 |
| 85 | ROCK | Chicago, Rock Island and Pacific Ry. Co. | added 7/1975; 1/1980; eliminated 7/1980 | | NAKINA |
| 86 | ROCK | Chicago, Rock Island and Pacific Ry. Co. | added 7/75; 1/80; eliminated 7/80 | | NRHS |
| 87 | ROCK | CHICAGO, ROCK ISLAND & PACIFIC RAILROAD (ROCK ISLAND) | | | PWRC |
| 88 | ROCK | Chicago, Rock Island and Pacific Railroad | | | RSRV |
| 89 | ROCK | Chicago, Rock Island and Pacific Ry. Co | 1975 - 1980 | USA | TRAFFIC |
| 90 | ROCKLAND | Rockland Coaches | A Coach USA company | USA | TRAFFIC |
| 91 | ROCL | ROSS, C L INC | | | SCAC3 |
| 92 | ROCL | RAPID OCEAN CO LTD | | | SCAC4 |
| 93 | ROCM | RICH OIL COMPANY INC | | | SCAC4 |
| 94 | ROCM | Republic of China Marine Corps | | RC | TRAFFIC |
| 95 | ROCN | ROCOR TRANSPORTATION COMPANIES | | | SCAC3 |
| 96 | ROCN | RORO COMPANY LTD | | | SCAC4 |
| 97 | ROCO | ROC MOVING & STORAGE | | | SCAC3 |
| 98 | ROCO | ROC MOVING & STORAGE | | | SCAC4 |
| 99 | ROCO | | | X | TRAFFIC |
| 100 | ROCQ | ROCKFORD-AURORA MOTOR SERVICE INC | | | SCAC3 |
