The Israel Aerospace Industries (IAI) Westwind was originally designed in the United States by Aero Commander as a development of its twin-propeller namesake aircraft, first flying on 2 January 1963 as the Aero Commander 1121 Jet Commander. It was of broadly conventional business jet arrangement, with two engines mounted in nacelles carried on the rear fuselage. However the wings were mounted halfway up the fuselage instead of the typical low-wing arrangement of aircraft in this class. After successful testing, the aircraft was put into series production with deliveries to customers beginning in early 1965.

Shortly thereafter, Aero Commander was acquired by North American Rockwell. The Jet Commander created a problem, since Rockwell already had an executive jet of its own design, the Sabreliner, and could not keep both in production because of anti-trust laws. It was therefore decided to sell off the rights to the Jet Commander, which were purchased by IAI in 1968.

Unfinished Jet Commander 1121's
Photo: Robert Deering 1971
Willy Post Airport (PWA)
Oklahoma City, Oklahoma

Jet Commander production amounted to 150 aircraft in the United States and Israel before IAI undertook a series of modifications to create the 1123 Westwind. These included stretching the fuselage and increased maximum takeoff, maximum landing, and maximum zero-fuel weights, with the wing modified to incorporate double-slotted flaps and drooped leading edges and tip tanks. The trimmable horizontal stabiliser was also modified to have increased span and more travel. Not long after the aircraft went into production, the original turbojet engines were replaced by more fuel-efficient Garrett TFE731 turbofans There were also numerous airframe modifications, such as drooped leading edges on the wings, a dorsal fin, revised engine pylons and nacelles, and further increases in maximum takeoff, maximum landing, and maximum zero-fuel weights. With improvements to a number of onboard systems incorporated as well, these changes resulted in the 1124 Westwind delivered from 1976.

In 1976, in the wake of the terrorist takeover of the Savoy hotel in Tel Aviv, the Israeli Air Force decided to use the Westwind as the basis for a maritime patrol aircraft, which became known as the IAI Sea Scan.

In 1980 deliveries of the Model 1124A commenced; modifications included a new wing centre-section and the addition of winglets to the tips. The revamped aircraft was called the Westwind II, replacing the original design in production. IAI built its last Westwind in 1987, after a total of 442 Jet Commanders and Westwinds had been built, switching production to the Astra.