| 1 | DUK | Ducair, S.A. | Callsign: Lion King, Ceased operations. | L | AVCODES |
| 2 | DUK | Ducair | | | ICAO1 |
| 3 | DUKA | DUCK'S AGRO LTD | | | SCAC4 |
| 4 | DUKB | DUNKEL BROS MACHINERY MOVING INC | | | SCAC4 |
| 5 | DUKD | DUKES, DAN TRUCKING INC | | | SCAC4 |
| 6 | DUKE | DUKE OIL COMPANY INC | | | SCAC4 |
| 7 | DUKG | DUDLEY TRUCKING | | | SCAC4 |
| 8 | DUKK | DUKE TRUCKING | | | SCAC4 |
| 9 | DUKL | DUKE TRUCKING LLC | | | SCAC4 |
| 10 | DUKOL | DUKOL Ostrava, s.r.o. | | CZ | VKM |
| 11 | DUKS | DUCKS TRUCKING INC | | | SCAC4 |
| 12 | DUKX | The Dupps Co. | added 11/1973; 1/1975-7/2000; eliminated 10/2003; 7/2005 (not listed) | | NAKINA |
| 13 | DUKX | Duke, Inc. | added 4/1967; 4/1970; eliminated 11/1973 | | NAKINA |
| 14 | DUKX | Duke, Inc. | added 4/67; 4/70 | | NRHS |
| 15 | DUKX | The Dupps Co. | 1/75-7/2000 | | NRHS |
| 16 | DUKX | DUPPS COMPANY [DUKE, INC.] | | | PWRC |
| 17 | DUKX | Dupps | | | RSRV |
| 18 | DUKX | DUPPS COMPANY | | | SCAC4 |
