| 1 | PSR | Express, Joint-Stock Aircompany | Callsign: Exavia, | RUS | AVCODES |
| 2 | PSR | Polestar Aviation | | | ICAO1 |
| 3 | PSR | Pittsburg & Shawmut R.R., Inc. | added 7/1996; 7/2000; eliminated 4/2004; 7/2005 | | NAKINA |
| 4 | PSR | Petaluma & Santa Rosa R.R. Co. | 7/1965-10/1966 & 1/1975-1/1980; eliminated 10/1984 | | NAKINA |
| 5 | PSR | Petaluma & Santa Rosa R.R. Co. | 7/65-10/66 & 1/75-1/80; eliminated 10/84 | | NRHS |
| 6 | PSR | Pittsburg & Shawmut R.R., Inc. | added 7/96; 7/2000 | | NRHS |
| 7 | PSR | *PETALUMA & SANTS ROSA RAILROAD CO. | | | PWRC |
| 8 | PSR | *PITTSBURG & SHAWMUT RAILROAD | | | PWRC |
| 9 | PSR | +BUFFALO & PITTSBURGH RAILROAD, INC. | | | PWRC |
| 10 | PSR | Pittsburg and Shawmut Railroad | | | RSRV |
| 11 | PSR | The Pittsburgh & Shawmut R.R. Co. | Real: PS | USA | TRAFFIC |
| 12 | PSRE | P S R ENTERPRISES INC | | | SCAC3 |
| 13 | PSRG | P & S TRUCKING INC | | | SCAC4 |
| 14 | PSRJ | PSR LEASING INC | | | SCAC4 |
| 15 | PSRK | PROSPERITY TRUCKING CO. | | | SCAC3 |
| 16 | PSRK | PROSPERITY TRUCKING CO | | | SCAC4 |
| 17 | PSRM | PACIFIC SOUTHWEST RAILWAY MUSEUM (SAN DIEGO RAILROAD MUSEUM) | | | PWRC |
| 18 | PSRM | POST ROAD MOVERS | | | SCAC3 |
| 19 | PSRO | PURSER OIL CO INC | | | SCAC4 |
| 20 | PSRQ | PROTOSTAR LOGISTICS INC | | | SCAC4 |
| 21 | PSRR | PACIFIC SUN RAILROAD LLC | | | SCAC4 |
| 22 | PSRS | PATTERSON, R S | | | SCAC4 |
| 23 | PSRU | PARATORI S.P.A. | | I | BIC |
| 24 | PSRV | PORTSERV TRANSPORTATION COMAPNY | | | SCAC3 |
| 25 | PSRV | PORTAL SERVICE CO INC | | | SCAC4 |
| 26 | PSRX | Puget Sound Butter & Egg Co. (Union Refrigerator Transit Co.) | 7/1935 | | NAKINA |
| 27 | PSRX | Puget Sound Refrigerator Line | 7/1932 | | NAKINA |
| 28 | PSRX | *PUGET SOUND REFRIGERATOR LINE | | | PWRC |
| 29 | PSRX | *PETALUMA & SANTA ROSA RAILROAD CO. (OUT OF OPERATION) | | | PWRC |
| 30 | PSRY | POINTS, T R TRUCKING | | | SCAC4 |
