If you get hired by a major with less than ten years remaining before mandatory retirement, do you still get retiree travel, medical, etc? If so, what are the requirements? Thanks

Depends on the major.

But generally in order to retire and obtain travel bennies in the industry, you have to have worked there at LEAST ten years and be at LEAST age 55.

Perhaps some have a waiver for folks who are to old to get the ten years, but you'd probably have to have someone at each airline you're interested in research that.

Delta pilots must have been employed 10yrs (not including any LOA's) and at least age 50 to receive retiree pass benefits unless your part of some special "retire early" programs the company can offer..... but not to pilots anytime soon.