The following designations and their abbreviations have been used by Marine helicopter squadrons. For those not familiar with this system, the first letter, either V for fixed-wing, or H for helicopter indicates type of aircraft flown. This is followed by one or more letters to indicate the type of squadron. Marine squadrons add an M following the type designation. (HT= Helicopter Training Squadron (Navy); HMT=Marine Helicopter Training Squadron).

HMA Marine Attack Helicopter Squadron  (1971 - 86)

HMH Marine Heavy Helicopter Squadron  (1962 - present)

HMHT Marine Heavy Helicopter Training Squadron  (1966 - 1972)

HML Marine Light Helicopter Squadron (1968 - 1994)

HMLA Marine Light Attack Helicopter Squadron (1983 - present)
-- Note: The two East Coast squadrons (167 and 269) insist on the non-standard "HML/A" designation.

HMM Marine Medium Helicopter Squadron  (1962 - present)

HMMT Marine Medium Helicopter Training Squadron (1966 - 72/1999 - present)

HMO Marine Helicopter Observation Squadron (not used) This was the proposed designation for the Marine Observation Squadrons when they switched from fixed-wing operations to helicopters in the 1950s. This change never occured.

HMR Marine Helicopter Transport Squadron (1951 - 62)

HMR(C) Marine Helicopter Transport Squadron (Composite)(1956 - 58) Only 3 squadrons were so designated and were used in the reconaissance role. Not used by Reserves.

HMR(L) Marine Helicopter Transport Squadron (Light)(1956 - 62). Designation was not used by Reserves.

HMR(M) Marine Helicopter Transport Squadron (Medium) (1957 - 62). Not used by Reserves.

HMX Marine Helicopter Squadron (1947 - present).

VMM Marine Medium Tiltrotor Squadron (2006 - present).

VMMT Marine Medium Tiltrotor Training Squadron (1999 - present). 1 squadron.

VMO Marine Observation Squadron (1943 - 1994). Helicopter use began in 1950 and ended in 1972.

VMX Marine Tilt-Rotor Test and Evaluation Squadron (2003 - present). 1 squadron.