heli - hour
- helical gear
- helicopter
- helicopter accident
- helicopter aerodrome
- helicopter approach height
- helicopter deck
- helicopter electromagnetics
- helicopter engineering
- helicopter landing deck
- helicopter landing platform
- helicopter lift
- helicopter logging operation
- helicopter operator
- helicopter overflight height
- helicopter pilot
- helicopter platform
- helicopter protected zone
- helicopter survey
- helicopter traffic zone
- helicopter transport
- helicopter yarding
- helicopter-to-ground data communications
- helicopter-type landing
- helideck
- heliocentric transfer altitude
- helipad
- heliport
- heliport deck
- helistop
- helium
- helium arcjet
- helmet
- hemispherical dome
- henry
- HEO mass
- HEO observatory
- HEO satellite
- HEO telescope
- HEO transportation
- HEO-to-LEO transfer
