I have one friend who went from police officer (cashed out his pension for flight school) to airline pilot and another who went from airline pilot (at the regionals where he was barely able to pay bills) to the police department for a large raise and so he could be home every night or day if he had the night shift. I guess if you only spent a few thousand on training it would be an easier choice to give up flying, but the average civilian trained pilot now probably has well over 50K in flight school alone not including college/ university costs. That said, I've seen quite a few pilots give up when their careers were stalled at the regionals and I've heard of some furloughed major airline pilots giving it up when the only pilot positions they could find were at the regional level and they just couldn't afford to go back to that pay level with families to take care of, but I'd say it's pretty rare for airline pilots to become police officers in general. Most of the pilots I know who gave it up either went back to college or got into real estate or became general contractors trying for the big bucks.