The starting point for what became the very symbol of the "biz jet" started life as an abortive attempt by a Swiss aircraft company to build a new ground-attack fighter aircraft, the FFA P-16 of 1955. Although this effort proved unsuccessful and by 1960 efforts to produce the warplane had ceased, the basic structure of this aircraft was seen by Bill Lear and his team as a good starting point to the development of a business jet, which was originally intended to be called the SAAC-23.
The wing with its distinctive tip fuel tanks and landing gear of the first Learjets were little changed from those used by the Swiss fighter prototypes. The tooling for building the aircraft was purchased and moved to Wichita, Kansas, United States, in 1962. On 7th February, assembly of the first Learjet was begun. The next year, the company was renamed the Lear Jet Corporation.
The original Learjet 23 was a six to eight seater and first flew on 7th October 1963, with the first production model being delivered in October 1964. Just over a month later, Lear Jet became a publicly-owned corporation. Several derived models followed, with the Learjet 24 first flying on 24th February 1966 and the Model 25 first flying on 12th August 1966. In September of the same year, the company was renamed Lear Jet Industries Inc.
On 10th April 1967, all of Bill Lear's assets he held approximately 60% of the company (US$27 million) were acquired by the Gates Rubber Company of Denver, Colorado, United States. However, he remained on the board until April 1969. Later in 1969, the company was merged with Gates Aviation and the company name was changed to Gates Learjet Corporation. In 1971, the first Model 25 powered by a Garrett TFE731-2 turbofan engine was flown. This aircraft later became the successful Learjet 35.