| 1 | ROP | Royal Oman Police | | OM | AVCODES |
| 2 | ROP | Royal Oman Police | | | ICAO1 |
| 3 | ROP | RAIL OPERATIONS SRL | | RO | VKM |
| 4 | ROPA | RONSON TRANSPORTATION INC | | | SCAC3 |
| 5 | ROPAG | ROP Roth AG | | DE | VKM |
| 6 | ROPAN | EUROPAN PROD SA | | RO | VKM |
| 7 | ROPC | ROGERS PETRO-CHEM CO | | | SCAC3 |
| 8 | ROPE | ROMERO, PAT FEEDS AND SUPPLY | | | SCAC3 |
| 9 | ROPE | ROTATION POWER & EQUIPMENT | | | SCAC4 |
| 10 | ROPG | ROYAL PROCESSING CO INC | | | SCAC3 |
| 11 | ROPN | ROSE TRANSPORTATION INC | | | SCAC3 |
| 12 | ROPR | ROSE TRANSPORTATION INC | | | SCAC3 |
| 13 | ROPS | ROCAROL PARCEL SYSTEM | | | SCAC3 |
| 14 | ROPT | ROPPE TRANSPORTATION CORPORATION | | | SCAC3 |
| 15 | ROPX | Rail Operators, Inc. | added 7/1993; 1/1994; eliminated 4/1997; 7/2000 (not listed) | | NAKINA |
| 16 | ROPX | Rail Operators, Inc. | added 7/93; 1/94; eliminated 4/97; 7/2000 | | NRHS |
| 17 | ROPX | RAIL OPERATORS, INC. | | | PWRC |
| 18 | ROPX | Rail Operators | | | RSRV |
