The Bell / Boeing V-22 Osprey is without a doubt one of the most unconventional aircraft ever designed, and the first tilt-rotor plane to enter military service anywhere. The tilt-rotor concept in effect makes the V-22 a helicopter/transport hybrid capable of vertical takeoff and then horizontal flight once airborne thanks to a triplex fly-by-wire system, thus making it ideal for service with the US Marine Corps (its primary user). It also shares the high-shoulder wing configuration with lateral fairings of conventional transports and is capable of carrying both cargo payloads as well as paratroopers which descend though a rear ramp rather than side doors like a helicopter due to the extreme downdraft of the propellers. Nevertheless and in spite of its revolutionary design, the V-22 has suffered from various controversies regarding its performance and stability including a number of embarrassing (and fatal) accidents which have delayed production significantly. It was only until 2005 when the first Marine unit began converting from helicopters to the V-22, a process which will continue well into the next decade.

First fligth of the prototype V-22 (which was based on the experimental Bell XV-15) was on 19 March 1989 but took well over a decade and a half before it entered service with the USMC where it is known as the MV-22A. It is also expected to enter service with the USN as the HV-22A for search-and-rescue and special operations as well as with the USAF with the CV-22A designation.