| 1 | OLD | Beijing Orenda Tribe General Aviation Co., Ltd. | Callsign: Air Orenda, | PRC | AVCODES |
| 2 | OLDB | OLD BAY TRANSFER | | | SCAC3 |
| 3 | OLDB | OLD BLACKSMITH SHOP, THE | | | SCAC4 |
| 4 | OLDC | OLD COLONY FILM TRANSFER CORP | | | SCAC3 |
| 5 | OLDE | OLD DUTCH EXPRESS INC | | | SCAC3 |
| 6 | OLDE | OLDE TOWN EXPRESS | | | SCAC4 |
| 7 | OLDH | OLDHAM, JAY F AND SON, INC | | | SCAC3 |
| 8 | OLDH | OLDHAM, JAY F AND SON, INC | | | SCAC4 |
| 9 | OLDHCT | Oldham Corporation Passenger Transport | | GB | TRAFFIC |
| 10 | OLDI | OLD IRON | | | SCAC4 |
| 11 | OLDJ | OLDHAM, JACK OIL INC | | | SCAC4 |
| 12 | OLDK | O L D TRUCKING | | | SCAC3 |
| 13 | OLDK | OLDENKAMP TRUCKING | | | SCAC4 |
| 14 | OLDL | OLDLAND DISTRIBUTING | | | SCAC3 |
| 15 | OLDO | OLDOVER CORPORATION | | | SCAC3 |
| 16 | OLDOP | OLOMOUCKÁ DOPRAVNI s.r.o. | | CZ | VKM |
| 17 | OLDP | OLD SCHOOL EXPRESS | | | SCAC4 |
| 18 | OLDQ | OLD DOMINION STEVEDORING CO | | | SCAC3 |
| 19 | OLDR | OLD RELIABLE TRANSPORT INC | | | SCAC3 |
| 20 | OLDR | OLD RELIABLE TRANSPORT INC | | | SCAC4 |
| 21 | OLDS | OLD SOUTH FREIGHT SERVICE INC | | | SCAC3 |
| 22 | OLDS | OLIVER, L D SEED CO INC | | | SCAC4 |
| 23 | OLDT | OLD SOUTH TRANSPORTATION CO INC | | | SCAC3 |
| 24 | OLDW | OLD WEST HARDWARE | | | SCAC4 |
| 25 | OLDX | Old Line Holding Co., Inc. | added 1/1992; 1/1994-7/2000; eliminated 10/2004; 7/2005 (not listed) | | NAKINA |
| 26 | OLDX | Old Line Holding Co., Inc. | added 1/92; 1/94-7/2000 | | NRHS |
| 27 | OLDX | OLD LINE HOLDING COMPANY, INC | | | PWRC |
| 28 | OLDX | Old Line Holding | | | RSRV |
