Bréguet 941 / McDonnell 188 first flown in 1961 demonstrating its STOL capabilities

The Breguet 941 is a French four-engine turboprop short takeoff and landing (STOL) transport aircraft developed by Breguet in the 1960s. Although widely promoted, both by Breguet in France and by McDonnell Aircraft and McDonnell Douglas in the United States, it was not built in large numbers; only one prototype and four production aircraft were built.

In the late 1940s and early 1950s, the French aviation pioneer Louis Charles Breguet developed a concept for a short takeoff and landing (STOL) aircraft using four free-turbine turboshaft engines to drive a common powershaft, which, in turn drove four oversize propellers, which were evenly spaced along the leading edge of the wing with large, full-span, slotted flaps, with the arrangement known as "l'aile soufflée" or blown wing.

An initial, experimental prototype, powered by four Turbomeca Turmo II engines, the Breguet 940 Integral, first flew on 21 May 1958, and was used to prove the concept, demonstrating excellent short field performance. This led to an order being placed in February 1960 for a prototype of an aircraft employing the same concept, but capable of carrying useful loads. This aircraft, the Breguet 941, first flew on 1 June 1961.

Testing of this prototype resulted in an order for four improved production aircraft, the Breguet 941S for the French Air Force, first flying on 19 April 1967. These were fitted with more powerful engines and a modified rear cargo door to allow for air-dropping of stores. McDonnell Aircraft acquired a production licence for the 941 in the United States and began marketing the aircraft with minimal changes as the McDonnell 188.

The 941 prototype was tested extensively in both France and the United States. McDonnell conducted demonstrations with the prototype in late 1964 and again in early 1965. The aircraft was evaluated by both NASA and the US military, but no orders were placed. McDonnell Douglas continued these efforts, using a production 941S for limited passenger operations for two months in 1968 with Eastern Air Lines between busy urban centers in the northeast U.S. The following year, this same aircraft was tested by American Airlines and then by the Federal Aviation Administration to evaluate the STOLport concept for operation from small city airports.[10] Despite these tests, the company found that airlines were primarily interested in operating jets from conventional airports, and did not embrace the novel STOLport concept; no sales resulted and none of the proposed upgraded versions left the drawing boards.