Aircraft capable of vertical take-off and landing (VTOL) without needing a runway are, in theory, an ideal solution for the military. These VTOL crafts need less physical space and infrastructure to become airborne compared to conventional planes. This allows for more fighters on a single aircraft carrier or the establishment of smaller airports in more remote areas.

Although VTOL technology originated from military applications, leading to the development of the long-delayed F-35B, it has also become an appealing choice for private and civil uses. This is especially true for potential "air taxis" or "flying cars" that would utilize helipads but are not precisely helicopters.

A vertical take-off and landing (VTOL) aircraft is capable of hovering, taking off, and landing in a vertical manner. This category encompasses various types of aircraft, such as fixed-wing aircraft, helicopters, and other rotor-powered vehicles.

Examples include cyclocopters and tiltrotors. Certain VTOL aircraft are capable of functioning in additional modes, such as CTOL (conventional take-off and landing), STOL (short take-off and landing), and/or STOVL (short take-off and vertical landing). However, some aircraft, like certain helicopters, are limited to VTOL operations, because they lack landing gear designed for horizontal movement. VTOL is a category within V/STOL (vertical and/or short take-off and landing).

Bell Boeing V-22 Osprey

Apart from the widespread helicopter, there are currently two types of VTOL aircraft in military service: those utilizing a tiltrotor, like the Bell Boeing V-22 Osprey, and those employing directed jet thrust, such as the Harrier family and the new F-35B Lightning II Joint Strike Fighter (JSF). In the civilian sector, only helicopters are generally in use at present, although some other types of commercial VTOL aircraft have been proposed and are under development as of 2017. Typically, VTOL aircraft capable of STOVL prefer it whenever possible, as it usually allows for a significant increase in take-off weight, range, or payload compared to pure VTOL.

Harrier

The concept of vertical flight has existed for millennia, with designs for a VTOL (helicopter) appearing in Leonardo da Vinci's sketches. Manned VTOL aircraft, initially as basic helicopters, first took flight in 1907, but it wasn't until after World War Two that they were perfected.

Leonardo da Vinci's sketch

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In addition to helicopter development, various methods have been explored to create practical aircraft with vertical take-off and landing capabilities. These include Henry Berliner's 1922–1925 experimental horizontal rotor fixed-wing aircraft, Nikola Tesla's 1928 patent, and George Lehberger's 1930 patent for relatively impractical VTOL fixed-wing airplanes with tilting engines. In the late 1930s, British aircraft designer Leslie Everett Baynes received a patent for the Baynes Heliplane, another tilt rotor aircraft. In 1941, German designer Heinrich Focke began work on the Focke-Achgelis Fa 269, which featured two rotors that tilted downward for vertical takeoff, but wartime bombing interrupted its development.

Convair XFY-1 Pogo in flight

In May 1951, Lockheed and Convair were both awarded contracts to design, build, and test two experimental VTOL fighters. Lockheed developed the XFV, while Convair created the Convair XFY Pogo.

Both experimental programs reached flight status and conducted test flights from 1954 to 1955, before the contracts were terminated. Similarly, the X-13 VertiJet underwent a series of test flights between 1955 and 1957, but met the same outcome.

During the 1950s, the use of vertical fans powered by engines was explored. The US developed an aircraft where jet exhaust powered the fans, whereas British projects, which were not constructed, proposed fans driven by mechanical connections to the jet engines.

Bell XV-15

NASA has operated other VTOL vehicles like the Bell XV-15 research craft (1977), similar to those used by the Soviet Navy and Luftwaffe. Sikorsky experimented with an aircraft called the X-Wing, which took off like a helicopter. During flight, the rotors would stop and serve as wings, offering lift alongside the fixed wings. The Boeing X-50 is a Canard Rotor/Wing prototype that employs a comparable concept.

Another British VTOL project was the gyrodyne, which features a rotor powered during take-off and landing, but freewheels during flight, with separate engines providing forward thrust. Beginning with the Fairey Gyrodyne, this type of aircraft eventually developed into the larger twin-engined Fairey Rotodyne. The Rotodyne used tipjets to power the rotor during take-off and landing, and then employed two Napier Eland turboprops with conventional propellers mounted on large wings to provide propulsion. The wings helped to reduce the load on the rotor during horizontal flight.

The Rotodyne was developed to combine the efficiency of a fixed-wing aircraft at cruise with the VTOL capability of a helicopter to provide short haul airliner service from city centres to airports.

Rotodyne

The first production tiltrotor aircraft CL-84-1 (CX8402) on display at the Canada Aviation and Space Museum in Ottawa, Ontario

The CL-84 was a Canadian V/STOL turbine tilt-wing monoplane developed and produced by Canadair from 1964 to 1972. In 1968, the Canadian government ordered three improved CL-84s, known as the CL-84-1, for military evaluation. Between 1972 and 1974, this version was showcased and assessed in the United States on the aircraft carriers USS Guam and USS Guadalcanal, as well as at various other locations.[citation needed] These trials included military pilots from the United States, the United Kingdom, and Canada. During the tests, two of the CL-84s crashed due to mechanical issues, but no lives were lost in these incidents. Ultimately, no production contracts were secured.

Although tiltrotors such as the Focke-Achgelis Fa 269 of the mid-1940s and the Centro Técnico Aeroespacial "Convertiplano" of the 1950s reached testing or mock-up stages,

the V-22 Osprey is considered the world's first production tiltrotor aircraft. It has one three-bladed proprotor, turboprop engine, and transmission nacelle mounted on each wingtip. The Osprey is a multi-mission aircraft with both a vertical take-off and landing (VTOL) and short take-off and landing capability (STOL). It is designed to perform missions like a conventional helicopter with the long-range, high-speed cruise performance of a turboprop aircraft. The FAA classifies the Osprey as a model of powered lift aircraft.

Attempts were made in the 1960s to develop a commercial passenger aircraft with VTOL capability. The Hawker Siddeley Inter-City Vertical-Lift proposal had two rows of lifting fans on either side. However, none of these aircraft made it to production after they were dismissed as too heavy and expensive to operate.

Uber has expressed interest in VTOL technology for taxis with Airbus as a potential partner. A German company, Lilium, has had successful test runs and the city of Dubai wants to incorporate VTOL planes into future transportation solutions.

Maybe someday the flying cars will actually arrive.