The SubSonex Personal Jet concept was first unveiled at EAA AirVenture Oshkosh 2009. After successful pairing with the PBS TJ-100 engine (the same Czech-built engine that powers Carlton's Super Salto and BonusJet jet-powered gliders), the SubSonex jet aircraft prototype, JSX-1, made its first flight on August 10, 2011 at Wittman Airport in Oshkosh, Wisconsin. Piloted by Bob Carlton. The flight lasted approximately 14 minutes and focused on low-end speed, including stalls and low approaches in the landing configuration. The JSX-1 completed a successful flight test program in 2012.
Through the course of a series of high-speed taxi tests, Sonex design team has identified some issues with controllability of the aircraft in the transition phase approaching takeoff speeds, and has decided to enter a thorough design review process aimed at making the aircraft easier to handle for the average recreational pilot.
The Subsonex originally sported a tandem landing gear with outrigger gear on each wing tip.
Due to the increased power offered by the new PBS TJ-100 engine selected for the SubSonex, it was determined that a tricycle gear configuration would be needed to increase yaw stability on the ground in the transition phase approaching takeoff speeds.
During Air Venture 2010, it was presented with the new fixed tricycle landing gear and the PBS TJ-100 turboJet engine.