| 1 | PEP | Pena Transportes Aereos, S.A. | IATA: 5P, Callsign: Aero Pena, IATA Prefix: 308, Founded and Commenced operations in 1995. Name changed to PENTA - Pena Transportes Aereos S.A. IATA designator reinstated | BR | AVCODES |
| 2 | PEP | Portland Electric Power Co. | 7/1935-7/1954 | | NAKINA |
| 3 | PEP | Portland Electric Power Co. Lines (Central Public Service System) | 7/1932 | | NAKINA |
| 4 | PEP | Portland Electric Power Co. Lines (Pacific Northwest Public Service Co.) | 7/1930 | | NAKINA |
| 5 | PEP | Portland Electric Power Co. | 4/38-1/52 | | NRHS |
| 6 | PEP | *PORTLAND ELECTRIC POWER CP. (CENTRAL PUBLIC SERVICE SYSTEM; PACIFIC NORTHWEST PUBLIC SERVICE CO.] | | | PWRC |
| 7 | PEP | *PORTLAND TRACTION CO., PORTLAND RR & TERMINAL DIVISION | | | PWRC |
| 8 | PEPA | PERSONAL PACKAGE SERVICE INC | | | SCAC3 |
| 9 | PEPA | Perlen Papier AG | | CH | VKM |
| 10 | PEPD | PAPER PRODUCTS INC | | | SCAC3 |
| 11 | PEPE | PONY EXPRESS PETROLEUM INC | | | SCAC3 |
| 12 | PEPE | PEPE AUTOTRANSPORTES | | | SCAC4 |
| 13 | PEPF | PERRETI, PAT FREIGHT SERVICE INC | | | SCAC3 |
| 14 | PEPF | PEPE FREIGHT | | | SCAC4 |
| 15 | PEPI | PETRO PRODUCTS INC | | | SCAC3 |
| 16 | PEPJ | PEOPLES EXPRESS CO | | | SCAC3 |
| 17 | PEPK | PUBLIC EXPRESS PENGUIN TRUCKING | | | SCAC3 |
| 18 | PEPM | PEPE MILLWORK LTD | | | SCAC4 |
| 19 | PEPN | PEP-UP INC | | | SCAC4 |
| 20 | PEPO | POTOMAC ELECTRIC POWER CO | | | SCAC3 |
| 21 | PEPP | PEPPARD & VAN EMMERICK | | | SCAC3 |
| 22 | PEPQ | PEP SERVICES CO | | | SCAC3 |
| 23 | PEPR | PETROLEUM PRODUCTS TRANSPORTATION I | | | SCAC4 |
| 24 | PEPS | PITURA ENTERPRISES LTD | | | SCAC4 |
| 25 | PEPX | Peppers Refining Co. | 1/1945-7/1954; eliminated 10/1954 | | NAKINA |
| 26 | PEPX | Potomac Electric Power Co. | added 1/1975; 1/1975-7/2000; eliminated 7/2003; 7/2005 (not listed) | | NAKINA |
| 27 | PEPX | Peppers Gasoline Co. | 7/1935-1/1943 | | NAKINA |
| 28 | PEPX | Peppers Refining Co. | 4/38-1/52 | | NRHS |
| 29 | PEPX | Potomac Electric Power Co. | added 1/75; 1/75-7/2000 | | NRHS |
| 30 | PEPX | *PEPPERS REFINING CO. [PEPPERS GASOLINE CO.] | | | PWRC |
| 31 | PEPX | +POTOMAC ELECTRIC POWER CO | | | PWRC |
| 32 | PEPX | Potomac Electric Power | | | RSRV |
| 33 | PEPX | POTOMAC ELECTRIC POWER CO | | | SCAC4 |
| 34 | PEPY | PEP TRANSPORTATION | | | SCAC3 |
| 35 | PEPY | PEP TRANSPORTATION | | | SCAC4 |
| 36 | PEPZ | POTOMAC ELECTRIC POWER CO. | | | PWRC |