Bombardier introduced the Challenger 604 in 1995 as an improved and updated version of the Challenger 601. Approximately ten years later, in early 2006, production on the Challenger ended with the Challenger 605. Bombardier's Challenger 605 was an improvement upon the design of the 604 while retaining most structural and design features; almost all components are optimized with technologically advanced systems and functionalities. Simple Flying has compiled a list of five key differences between the Challenger 604 and 605.