No guarantee at all a major will hire you at 17.5. Some have, but simply math (date graduated college, etc) can telegraph your years of service to an airline even if they don't ask. With thousands of military and former military pilots on the property, they aren't clueless when it comes to AGR options, etc.

Now...I bailed at 14. But 6 years left was 2 assignments, perhaps a remote or a 365 thrown in for good measure. I "could" have gone AGR a couple years into it but chose not to (different story). With 1 tour to go...I'd strongly suggest staying, securing the retirement, and using the 2.5 years to network like crazy and get your ducks in a row. Being behind 2000 numbers at Delta or 1000 numbers at FDX might be frustrating, but 40-50k a year and the security should more than offset the loss. The danger is you bail--don't get hired--and suddenly are plugging away at a regional wondering why you did that. 10 year guy? I'd push you off the fence. 14 year guy? I would caution you about the risks, but offer some tales of folks who have done it well. 17.5 year? I'm wiping your face with a cold towel telling you to wake up and walk back into the ring for 2.5 more years...the final bell is about to ring. You can finish this fight...