Being passed over can be a blessing in disguise. First, your ADSC goes out the window. Secondly, you'll likely get a severance pay. I'd go to the guard/reserves. Assuming that you've completed (or will) PME, you'll be promotable in the guard/reserves since they have a separate board. Getting passed over on AD has no bearing in the guard/reserves, as far as I know. Apply to the airlines now and come up with the best possible separation date. Seniority is everything.