Conference realignment will never die. The Air Force Falcons are still a member of the Mountain West Conference and, according many accounts, committed to it for the long-term. However, a report from the Philadelphia Inquirer has the Falcons pegged as potential recruit:
The conference is expected to grow to 14 teams in 2015. That's when Navy joins for football only. Brigham Young or Air Force is expected to join Navy, according to multiple sources at the spring meetings.
Obviously, the first step in Air Force actually joining the Big East would be to say so. That isn't appearing on the horizon right now. And then there are other issues for Air Force to deal with. Chief among them would be the search for a new conference for the Olympic sports. Air Force, when it flirted earlier with the Big East, was reported as just being a football-only member, and there's nothing likely to change that if this wound up happening.
BYU would seem to be a better candidate since it is already a football independent and has a conference for its Olympic sports.
Still, at this point we're just talking about rumors again.