| 1 | AUN | Aviones Unidos, S.A. de C.V. | Callsign: Aviones Unidos, | MEX | AVCODES |
| 2 | AUN | Common Sky A & N Luftfahrt GmbH | Callsign: Common Sky, | D | AVCODES |
| 3 | AUN | Aviones Unidos | | | ICAO1 |
| 4 | AUNA | AUSTIN NORTH AMERICAN | | | SCAC3 |
| 5 | AUNC | AUTHENTIC TOURS INC | | | SCAC3 |
| 6 | AUND | ASTEN DISTRIBUTION | | | SCAC3 |
| 7 | AUNI | A A A UNIVERSAL INTERNATIONAL AUTO | | | SCAC3 |
| 8 | AUNK | AURORA TANKERS INTERNATIONAL LIMITE | | | SCAC4 |
| 9 | AUNL | ARUTRANS LLC | | | SCAC4 |
| 10 | AUNM | AUSTIN MOVERS | | | SCAC3 |
| 11 | AUNO | AUTOTRANSPORTES UNION | | | SCAC4 |
| 12 | AUNP | AUTOCON MOTORSPORTS | | | SCAC4 |
| 13 | AUNR | ASTROCIELO NEPTUNEA ARMADORA SA | | | SCAC3 |
| 14 | AUNU | ADVANCE INTERNATIONAL TRANSPORT | | | SCAC4 |
| 15 | AUNV | AURORA NAVIGATION S A PAMANA | | | SCAC3 |
| 16 | AUNW | Austin R.R. (Austin & Northwestern R.R. Co.) | added 1/1987; 1/1994 (not listed); eliminated 7/1996 | | NAKINA |
| 17 | AUNW | Austin R.R. (Austin & Northwestern R.R. Co.) | added 1/87; 1/94; eliminated 7/96 | | NRHS |
| 18 | AUNW | AUSTIN RAILROAD CO., INC. D/B/A AUSTIN & NORTHWESTERN | | | PWRC |
| 19 | AUNW | Austin and Northwestern Railroad | | | RSRV |
| 20 | AUNW | AUSTIN & NORTHWESTERN RAILROAD CO | | | SCAC3 |
