The Bombardier Challenger 600 began as a proof-of-concept business aircraft design from American aircraft pioneer Bill Lear. The design was subsequently purchased by Canadair, the predecessor to Bombardier, in the late 1970s. Canadair further refined the design and certified the aircraft in 1980. The type really “took off,” so to speak, with the follow-on Challenger 601, introduced in 1983, which replaced its predecessor’s Avro Lycoming engines with modern General Electric CF43-1A turbofans designed for high-utilization commercial airline service.
Though the early Lockheed Jetstar had four, most production business jets have two jet engines, mostly rear-mounted podded engine. If mounted below their low wing, it wouldn't allow sufficient engine clearance without a too long landing gear. The HondaJet is the exception with its over the wing engine pods. Dassault Falcon still builds three-engine models derived from the Falcon 50, and the very light jet market has seen several single-engine design concepts and the introduction of the Cirrus Vision SF50 in 2016.