| 1 | PHD | Duncan Aviation, Inc. | Callsign: Panhandle, | USA | AVCODES |
| 2 | PHD | Duncan Aviation | | | ICAO1 |
| 3 | PHD | Port Huron and Detroit R.R. Co. | 1/1975-7/2005; eliminated 10/2008 | | NAKINA |
| 4 | PHD | (PH&D) Port Huron and Detroit R.R. Co. | 4/1970 | | NAKINA |
| 5 | PHD | (PH&D) Port Huron and Detroit R.R. Co. | Apr-70 | | NRHS |
| 6 | PHD | Port Huron and Detroit R.R. Co. | 1/75-7/2000 | | NRHS |
| 7 | PHD | CSX TRANSPORTATION, INC. [CHESSIE SYSTEM; PORT HURON & DETROIT RAILROAD] | | | PWRC |
| 8 | PHD | Port Huron and Detroit Railroad (CSX Transportation) | | | RSRV |
| 9 | PHD | Port Huron and Detroit Railroad Company | City: Grodzisk Mazowiecki | USA | TRAFFIC |
| 10 | PHDB | PHYSICAL DISTRIBUTION SERVICES, INC. | | | SCAC3 |
| 11 | PHDB | PHYSICAL DISTRIBUTION SERVICE INC | | | SCAC4 |
| 12 | PHDC | PARHAM, H D CO INC | | | SCAC3 |
| 13 | PHDC | POLISH EXPRESS INC | | | SCAC4 |
| 14 | PHDH | PLATINUM HOME DELIVERY | | | SCAC4 |
| 15 | PHDI | PHIL-DI OF TEXAS | | | SCAC3 |
| 16 | PHDL | PHILLIPS, D L TRUCKING | | | SCAC3 |
| 17 | PHDN | PHIL-DAN TRUCKING | | | SCAC3 |
| 18 | PHDQ | PONDEROSA HEAVY DUTY TRUCKS INC | | | SCAC4 |
| 19 | PHDS | PITCHER, CARL L | | | SCAC4 |
| 20 | PHDT | P H D TRUCKING SERVICE INC | | | SCAC3 |
| 21 | PHDT | PICHARDO, D TRANSPORT | | | SCAC4 |
| 22 | PHDX | Phelps-Dodge Corp. | added 1/1960; 4/1961-1/1975; eliminated 10/1978 | | NAKINA |
| 23 | PHDX | Phelps-Dodge Corp. | added 1/60; 4/61-1/75; eliminated 10/78 | | NRHS |
| 24 | PHDX | PHELPS-DODGE CORP. | | | PWRC |
| 25 | PHDX | PHELPS DODGE CORP | | | SCAC3 |
