Crichton was pure civilian scientist despite his Commander rank.
He became an astronaut like his dad, and given how little they actually tell us about his origin he could very easily have served a stretch in the air force to get his degree much like James Rhodes from Iron Man
. And while he worked for IASA instead of NASA in a reality that had never heard fo the gravitic slingshot maneuver, I imagine as someone serving as an *ASA mission commander/pilot he had to fulfil the requirement of having accrued at least 1,000 hours pilot-in-command time in jet aircraft (given he was solo crew of Farscape 1
, he would be definition seem to have the highly desireable flight test experience).