The Air Force Falcons are among the teams the Big East has invited to join--albeit in a football-only capacity--as covered previously in this StoryStream, and it doesn't appear as though the service academy is in a hurry to act on the opportunity: Pete Thamel of the New York Times says "Air Force [is] in no rush." Further, he quotes Air Force athletic director Hans Mueh as saying, "There’s not [sic] real impetus to do anything but sit back and watch."
The Falcons (3-3, 0-2) are currently part of the Mountain West Conference, which they joined prior to the 1999 season. The Big East hoped to add them, the Navy Midshipmen, and the Army Black Knights in order to compensate for the departures of the Syracuse Orange and the Pittsburgh Panthers. Army's lack of interest only added more pressure to the conference to reshape itself.
The Big East may also invite the Central Florida Knights, who appear to be ready to use a tactic diametrically opposed to Air Force's, which is to say they're likely to accept in the immediate future, should the Big East make an offer.
Stay tuned to this StoryStream for future updates about the Big East's efforts to expand as they become available. The South Florida Bulls will soon have some new rivals.