Folding wing

[3] Since the monoplane supplanted the biplane in the late 1930s, virtually all fixed-wing aircraft designed for shipboard duty have been equipped with folding wings.

Notable exceptions include the SBD Dauntless, F2A Buffalo, and A4D/A-4 Skyhawk (all USN types); the Mitsubishi A5M and Yokosuka D4Y (Japanese); and the Sea Harrier (British).

The Grumman-patented Sto-Wing aftwards-folding wing folding system, pioneered on the Grumman F4F-4 Wildcat, has been used since World War II on a number of Grumman-designed carrier aircraft,[4][5] a version of which is still in use in the 21st century on the Grumman E-2 Hawkeye shipboard airborne early warning (AEW) aircraft and its C-2 Greyhound derivative.

Folding surfaces are rare among land-based designs and are used on aircraft that are too tall or too wide to fit inside service hangars.

Aircraft with ventral fins under the fuselage for stability which had to be folded for takeoff and landing include the Mikoyan-Gurevich MiG-23, the MiG-27, and the Vought XF8U-3 Crusader III.