| 1 | ITR | Frontier Commuter | Callsign: Out Back, Name changed from ITR Airlines, Inc. | USA | AVCODES |
| 2 | ITR | ITR Airlines, Inc. | Callsign: Out Back, Name changed to Frontier Commuter | USA | AVCODES |
| 3 | ITR | Frontier Commuter | | | ICAO1 |
| 4 | ITR | IOWA TERMINAL RAILROAD CO. | | | PWRC |
| 5 | ITRA | ISABELLE TRANSPORT | | | SCAC4 |
| 6 | ITRC | IOWA TERMINAL RAILROAD CO., CHARLES CITY DIV. | | | PWRC |
| 7 | ITRC | INDUSTRIAL TRANSFER COMPANY | | | SCAC1 |
| 8 | ITRC | INLAND TRANSPORTATION CORP | | | SCAC4 |
| 9 | ITRD | INTER FREIGHT INC | | | SCAC4 |
| 10 | ITRE | IBP TRANSPORTATION REFRIGERATED EXP | | | SCAC4 |
| 11 | ITRG | INGRAM TRUCKING | | | SCAC4 |
| 12 | ITRH | INBAL TRUCKING | | | SCAC4 |
| 13 | ITRJ | INTERSTATE 48 TRANSPORTATION | | | SCAC4 |
| 14 | ITRK | ISRAELS TRUCKING | | | SCAC4 |
| 15 | ITRL | INTERNATIONAL TRANSPORT | | | SCAC4 |
| 16 | ITRM | IOWA TERMINAL RAILROAD CO., MASON CITY DIV. | | | PWRC |
| 17 | ITRM | I T R TRUCKING | | | SCAC4 |
| 18 | ITRN | INTERNATIONAL TRUCKING CO INC | | | SCAC4 |
| 19 | ITRO | INTER TRANSPORT | | | SCAC4 |
| 20 | ITRP | ITZELL TRANSPORT | | | SCAC4 |
| 21 | ITRR | INGERSON TRANSPORTATION | | | SCAC4 |
| 22 | ITRS | INTERSTATE TRUCK SERVICE INC | | | PWRC |
| 23 | ITRS | INLAND TERMINAL SERVICES OF WASHING | | | SCAC4 |
| 24 | ITRT | ITR ACOUSTIQUE INC | | | SCAC4 |
| 25 | ITRU | ITEL CONTAINERS INTERNATIONAL CORPORATION | | | PWRC |
| 26 | ITRU | Itel Containers International Corporation | | | RSRV |
| 27 | ITRU | INTERCON MODULAR LLC | | | SCAC4 |
| 28 | ITRUD | ISAR-TANK F.U.H Rudolf GdbR | | DE | VKM |
| 29 | ITRW | IBARRA TRUCKING | | | SCAC4 |
| 30 | ITRY | IMPERIAL TRUCKING | | | SCAC4 |
