The Learjet 23 was a high-speed, twin-engine business jet introduced in service in the United States in 1964. It was the first model produced by the Lear Jet Corporation and transported many of the rich and famous to their glamorous engagements. It triggered a revolution in the aviation world, creating a new market for fast and efficient small business aircraft. In a short space of time “Learjet” became a synonym for any private jet of any brand.

The Learjet 23 came about thanks to William “Bill” Powell Lear (1902 – 1978), an American inventor and entrepreneur. Among the many innovations to his credit were practical home radio, the aerial radio direction finder, 8-track stereo, various car radios, and the first jet autopilot. Although Lear was not an aeronautical engineer he had been flying since he was 30. He was almost 60 – an age when many are ready to retire – when he realised the market potential for small bizjets, despite lacklustre sales by pioneers like the Lockheed Jetstar.

In 1960, Lear moved to Switzerland and founded the Swiss American Aviation Company (SAAC). His aim was to build a private jet based on the FFA P-16 jet fighter – a straight-wing fighter-bomber prototype intended for the Swiss Air Force, but abandoned in 1959. However, impatient with the tardy pace of progress in Switzerland, Lear moved to Wichita, Kansas, where he built a design office and factory. His company was renamed Lear Jet Corporation, and the new aircraft became the Lear Jet (later Learjet) Model 23. At last the project began to pick up speed. From its first flight on October 7, 1963, the private jet needed just a year to enter service on October 13, 1964. Bill Lear immediately publicised it through official flight records. In May 1965, a Learjet 23 covered the nearly 4,000 km distance from Los Angeles to New York, and back, in 11 hours, 36 minutes. And in December 1965, another aircraft climbed to 40,000 feet in 7 minutes, 21 seconds – a feat which rivalled the capability of the latest US Air Force and Navy fighters of the day.

Indeed, the Learjet 23’s sleek, futuristic design, allmetal construction and superlative performance practically screamed “fighter jet”. Just like a fighter it could carry out a range of aerobatic manoeuvres. While the wing leading edge had a 13° sweep, it had a straight trailing edge. It had two pilots and could accommodate only 4-6 passengers. The plane was powered by two General Electric CJ610-4 singleshaft axial-flow turbojet engines with 8-stage compressor and 2-stage turbine, each generating 2,850 pounds of thrust. Its cruise speed was an impressive 834 km/h at 40,000 feet, comparable with that of the Boeing 707 airliner of the period. Its maximum range was 2,945 km.

However the Learjet 23 cabin was rather cramped, being just over four feet in both width and height. When questioned about this, Lear famously retorted, “You can’t stand up in a Cadillac either!” With its outstanding performance and looks, the Model 23 was an instant hit with the wealthy and influential. Indeed, its small size, high speed, low cost, and easy maintenance made it much more suitable for the early business and private jet market than its nearest rival the JetStar, a fourengine quadjet. Lear also mounted a savvy promotional campaign, giving free, well-publicised joyrides to numerous celebrities, which helped boost sales. However, the first three years of operation also saw many an accident. Most of these were not due to any aircraft design deficiency. It is just that some pilots were inadequately trained to handle such high-performance jets, which obviously had high stall and landing speeds.

Lear Jet built only 101 Model 23 aircraft, ending production within less than two years. More advanced designs were regularly introduced and improved on as technology evolved. The Model 25 which first took to the air in August 1966 could seat eight in comfort. It was this type, more than any other, which reinforced the Learjet’s place in the market. Learjet 25 production amounted to 369. By the 1970s, the Learjet sported a turbofan engine and, eventually, winglets that improved both performance and fuel economy.

In 1990, Canadian manufacturer Bombardier acquired the Learjet line and began producing further advanced models. However, bizjets gradually evolved into “an office, a workspace, or home space in the air where you can seamlessly enter the aircraft and carry on your day as if you were still on the ground,” as one industry executive put it. That required ample space, which is something Learjets did not have. In February 2021, hit by rising competition, Bombardier announced the end of Learjet production. The final aircraft was delivered in March 2022. Between 1962 and 2022, around 3,040 aircraft bearing the name Learjet were built. Today, over 2,000 Learjets are still on active flying duties.