| 1801 | PCTS | PETERS, CAL TRANSIT INC | | | SCAC3 |
| 1802 | PCTU | PC LOGISTIC SP. Z O.O. | | PL | BIC |
| 1803 | PCTW | PAC TRUCKING | | | SCAC3 |
| 1804 | PCTX | Pioneer Cement Co. of Texas | 1/1994-7/2005 (not listed) | | NAKINA |
| 1805 | PCTX | Pioneer Cement Co. of Texas | 1/94-7/2000 | | NRHS |
| 1806 | PCTX | PIONEER CEMENT CO. OF TEXAS, INC. [PIONEER CONCRETE OF TEXAS] | | | PWRC |
| 1807 | PCTX | Pioneer Cement of Texas | | | RSRV |
| 1808 | PCTX | PIONEER CONCRETE OF TEXAS, INC. | | | SCAC4 |
| 1809 | PCTY | PORT CITY TRANSPORTATION CO | | | SCAC3 |
| 1810 | PCTZ | PLUM CREEK TIMBER | | | PWRC |
| 1811 | PCTZ | PRICE TRANSFER, INC. | | | SCAC3 |
| 1812 | PCUB | PARAMOUNT CUBIC CO INC | | | SCAC3 |
| 1813 | PCUI | POLLUTION CONTROL UNLIMITED INC | | | SCAC3 |
| 1814 | PCUI | PATRIOT CARRIERS INC | | | SCAC4 |
| 1815 | PCUN | POCATELLO URBAN TRANSIT | | | SCAC3 |
| 1816 | PCUR | PRO COURIER INC | | | SCAC3 |
| 1817 | PCUS | POCONO COMMUTER SERVICE INC | | | SCAC3 |
| 1818 | PCUT | PRESCO AUTO TRANSPORT | | | SCAC3 |
| 1819 | PCUT | PITTSBURGH CUT FLOWER CO | | | SCAC4 |
| 1820 | PCV | Pacific Aviation (A' Asia) Pty Ltd. | Callsign: Pacav, | AUS | AVCODES |
| 1821 | PCV | Pacific Aviation (Australia) | | | ICAO1 |
| 1822 | PCVSA | PECOVASA RENFE MERCANCÍAS | | ES | VKM |
| 1823 | PCVU | PEACOCK CONTAINER BV | | NL | BIC |
| 1824 | PCVU | PEACOCK CONTAINER BV | | | SCAC4 |
| 1825 | PCW | Trans-Pacific Orient Airways Inc. | Callsign: Pacific Orient, | RP | AVCODES |
| 1826 | PCW | Trans-Pacific Orient Airways | | | ICAO1 |
| 1827 | PCW | Siemens Prüfcentrum Wegberg-Wildenrath | | DE | VKM |
| 1828 | PCWD | PACIFIC COAST WAREHOUSING LTD | | | SCAC4 |
| 1829 | PCWE | PACWEST DISTRIBUTING | | | SCAC4 |
| 1830 | PCWH | PACIFIC COAST TRUCK & WAREHOUSE INC | | | SCAC3 |
| 1831 | PCWH | PACIFIC COAST TRUCK AND WAREHOUSE I | | | SCAC4 |
| 1832 | PCWI | P C W INC | | | SCAC3 |
| 1833 | PCWN | PLUNKARD, C W & SONS | | | SCAC4 |
| 1834 | PCWP | Port Chester & White Plains Bus Co | | US-NY | TRAFFIC |
| 1835 | PCWQ | PARTIAL CONNECTION & WAREHOUSING IN | | | SCAC4 |
| 1836 | PCWR | OEARCEM WARREB & CO INC | | | SCAC3 |
| 1837 | PCWS | PACIFIC CHAMPION SERVICE CORP | | | SCAC3 |
| 1838 | PCWS | PACIFIC COAST WAREHOUSE SERVICES IN | | | SCAC4 |
| 1839 | PCWT | PAC WEST TRANSPORT SERVICES INC | | | SCAC4 |
| 1840 | PCX | Pacific Aviation Corporation | | USA | AVCODES |
| 1841 | PCX | Pacific Aviation (United States) | | | ICAO1 |
| 1842 | PCX | Packers Car Line Co. | added 4/1957; 10/1957-4/1970; eliminated 7/1972 | | NAKINA |
| 1843 | PCX | Pittsburgh Coal Carbonization Co. | 7/1935-1/1946 | | NAKINA |
| 1844 | PCX | Pelican Oil Refining Co., Inc. | 8/1920 | | NAKINA |
| 1845 | PCX | Pittsburgh Coal Carbonization Co. | Apr-38 | | NRHS |
| 1846 | PCX | Packers Car Line Co. | added 4/57; 10/57-4/70 | | NRHS |
| 1847 | PCX | *PELICAN OIL REFINING CO., INC. | | | PWRC |
| 1848 | PCX | *PITTSBURGH COAL CARBONIZATION CO. | | | PWRC |
| 1849 | PCX | *PACKERS CAR LINE CO. | | | PWRC |
| 1850 | PCXC | PACIFIC SEAS TRANSPORT INC | | | SCAC4 |
| 1851 | PCXE | PACIFIC XPRESS TRUCKING INC | | | SCAC4 |
| 1852 | PCXG | P & C TRANSPORTS LLC | | | SCAC4 |
| 1853 | PCXI | PACIFIC EXPRESS INC | | | SCAC3 |
| 1854 | PCXL | PACIFIC COAST EXPRESS LIMITED | | | SCAC4 |
| 1855 | PCXN | PC EXPRESS INC | | | SCAC4 |
| 1856 | PCXR | PACIFIC COAST EXPRESS | | | SCAC4 |
| 1857 | PCXS | PROCON EXPRESS LINES | | | SCAC4 |
| 1858 | PCXU | SHIRLSTAR CONTAINER TRANSPORT | | | SCAC4 |
| 1859 | PCXW | PROTECH EXPRESS TOWING | | | SCAC4 |
| 1860 | PCY | Pittsburgh, Chartiers & Youghiogheny Ry. Co. | 1/1975-1/1994; eliminated 7/1997; 7/2000-7/2005 | | NAKINA |
| 1861 | PCY | Pittsburgh, Chartiers & Youghiogheny Ry. Co. | 1/75-1/94; eliminated 7/97; 7/2000 | | NRHS |
| 1862 | PCY | PITTSBURGH, CHARTIERS & YOUGHIOGHENY RAILWAY CO. | | | PWRC |
| 1863 | PCY | Pittsburgh, Chartiers and Youghiogheny Railway | | | RSRV |
| 1864 | PCYA | PEREA CASTANEDA, AGRIPINO | | | SCAC4 |
| 1865 | PCYD | PORT CITY DRAYAGE INC | | | SCAC3 |
| 1866 | PCYE | PORT CITY ENTERPRISE LTD | | | SCAC4 |
| 1867 | PCYJ | PATTON, CYDNEY J | | | SCAC3 |
| 1868 | PCYL | PROCYCLE GROUP INC | | | SCAC4 |
| 1869 | PCYM | PITT COUNTRY MART INC | | | SCAC4 |
| 1870 | PCYN | PORT CITY SERVICES INC | | | SCAC4 |
| 1871 | PCYT | PORT CITY TRANSIT | | | SCAC4 |
| 1872 | PCYW | PORT CITY WAREHOUSE CORP | | | SCAC3 |
| 1873 | PCZX | PCZ CONSTRUCCIONES SA DE CV | | | PWRC |
| 1874 | PCZX | PCZ CONSTRUCCIONES SA DE CV | | | SCAC4 |
| 1875 | PD | Pemair | ICAO: PEM, Callsign: Pem-Air, | CDN | AVCODES |
| 1876 | PD | Pluto Airlines LLC | ICAO: PPL, Callsign: Pluto Air, Ceased Operations | UAE | AVCODES |
| 1877 | PD | Palau Rock Island Air | | PAL | AVCODES |
| 1878 | PD | Porter Airlines Inc. | ICAO: POE, IATA Designator changed to P3. | CDN | AVCODES |
| 1879 | PD | Porter Airlines (Canada) Limited | | CDN | AVCODES |
| 1880 | PDA | Podilia-Avia | Callsign: Podilia, | UA | AVCODES |
| 1881 | PDA | Podilia-Avia | | | ICAO1 |
| 1882 | PDAC | P D A CORPORATION | | | SCAC3 |
| 1883 | PDAC | PADDA CARRIERS INC | | | SCAC4 |
| 1884 | PDAH | PLUMLEY DELIVERY SERVICE LLC | | | SCAC4 |
| 1885 | PDAI | PDA INTERNATIONAL | | | SCAC3 |
| 1886 | PDAI | PRODUITS ANDALOS INC | | | SCAC4 |
| 1887 | PDAJ | PANCHOS DISTRIBUTING CO INC | | | SCAC4 |
| 1888 | PDAL | PALADINO, VINCE FARMS INC | | | SCAC4 |
| 1889 | PDAM | PLRS DE ACUNA S RL DE | | | SCAC4 |
| 1890 | PDAP | PARADA SHIPPING COMPANY LIMITED | | | SCAC3 |
| 1891 | PDAS | PANDAS DELIVERY | | | SCAC3 |
| 1892 | PDAS | PRODUCTION DESIGN INTERNATIONAL INC | | | SCAC4 |
| 1893 | PDAT | PANDA TRUCKING INC | | | SCAC4 |
| 1894 | PDAU | DALIAN JIFA BOHAI RIM CONTAINER LINES | | PRC | BIC |
| 1895 | PDAV | PORTER, DAVID | | | SCAC4 |
| 1896 | PDAX | Protex Industries, Inc. | added 10/1964; 7/1965-1/1975; eliminated 4/1978 | | NAKINA |
| 1897 | PDAX | Protex Industries, Inc. | 7/65-1/75; eliminated 4/78 | | NRHS |
| 1898 | PDAX | PROTEX INDUSTRIES, INC. | | | PWRC |
| 1899 | PDAX | PROTEX INDUSTRIES INC | | | SCAC3 |
| 1900 | PDAY | PARDUE, DANNY | | | SCAC4 |
