I made the mistake of waiting to apply until I was about 3 months out from being available after finishing my AF time. In the end it didn't matter; I got the interview and pretty much the first class I could have made. However, I heard from a friend of a friend that he applied with just about a year to go from his retirement date and not only got the interview, but an offer. This was with Delta during their last hiring period (circa 2010). In the end they stopped their short hiring period, and didn't pick up again anytime soon. Around a year later they rescinded the offer due to no hiring, but told him he'd be first in line for interviews when hiring started up again. He ended up retiring (instead of pushing it back) and going with FedEx.