If it was me, I'd stay in and get my 20 years as to lock in my pension which is guaranteed income for life. Airline jobs will always be there and can be treated more as a hobby that pays well on top of the military pension. Your friend will be about age 42 if he does the full 20 years in the Air Force, still leaves him with a 23 year career at a major airline when he separates. I know many guys who bypassed doing their 20 years in active duty to take a job with United back in the late 90's, they all regretted it. Who's to say there won't be a major downturn in the economy and history won't repeat itself. We don't know what the future holds but one thing is a fact, the military pension is guaranteed with 20 years. Good luck in whatever path your friend chooses.