| 1 | H4 | Inter Islands Airlines | ICAO: IIN, Designator H4 reinstated by IATA | CV | AVCODES |
| 2 | H4 | Hainan Airlines Company Limited | ICAO: CHH, Callsign: Hainan, IATA designator changed to HX | PRC | AVCODES |
| 3 | H4 | Heli Securite Helicopter Airline | ICAO: HLI, Callsign: Heli Saint-Tropez, Designator H4 recalled by IATA. | F | AVCODES |
| 4 | H4 | Seven Four Eight Air Services (K) Limited | ICAO: IHO, Callsign: Sefeas, IATA Prefix: 874, IATA designator changed to FE. | EAK | AVCODES |
| 5 | H4 | Raven Air, LLC d/b/a Island Hoppers Aerial Adventures | Designator H4 recalled by IATA. | USA | AVCODES |
| 6 | H4 | HiSky Europe | ICAO: HYS, Callsign: Sky Europe, | RO | AVCODES |
