I haven't done it, but here are some possible reasons dudes might drop long term mil leave...
- early years pay sucks in the airlines. If I didn't do the reserve gig as well, I would be making roughly 45% of what I made on active duty, and I'm at one of the higher-paying-in-the-first-year airlines. Makes it rough to keep any semblance of the lifestyle you were living before getting out without wiping out your savings. Mil pays much better. If a dude finds a opportunity after he got out to go back and make some decent pay at a job he enjoys, all while progressing in pay/seniority at an airline, he might do that. Pay jumps up after year one in the airlines, but it will take a while at most places to get back to what you were making before you got out.
- reserve at the airlines sucks. I'm spamming this site because I'm sitting in my crash pad watching my phone not ring and I'm bored senseless. 5 years from now, I hope I would be off reserve and holding a line...i.e. better quality of life.
- hours don't mean anything once you're in an airline for progression. there is no merit based progression like in the military, so it won't hurt upgrades to capt (as far as I know). It's all seniority...which is still accruing while you are on mil leave. If your seniority number can hold a seat/aircraft when you get back, you can bid it.
- As for the technician side and USERRA, can't speak much to it or whether it's possible/legal. As a technician, you will be put on mil status a decent amount so you will still be able to accrue points towards reserve/guard retirement. Unless you quit the airline, you obviously won't ever get the full civil service retirement, but if you stick it out through 20 years of reserve/guard service, you'll be able to pick up that retirement (and health care benefits) at age 60. If you go back full time for a few years, it makes it that much less you have to work 2 jobs at the same time to get to that 20 year point for reserve retirement. Working 2 jobs sucks.
- job satisfaction...some dudes didn't have any in the military, but many really did. Sometimes it's tough to find the same kind of job satisfaction on the outside, in my opinion.
I think it's very poor form (although legal) to get hired by an airline with the prior INTENTION of dropping 5 years of mil leave right away or soon after hire. But things happen, opportunities arise, and we're at war. If a great opportunity drops in a dude's lap, I don't fault him for taking it.