Stars and Stripes says the US Air Force is looking at a new paradigm in demographics for the coming years:  fewer fighter pilots.  The reduction is attributable to several causes:

U.S. Air Force officials say the number of fighter pilots is likely to decline in coming years, due in part to fewer aircraft and training opportunities, fighter pilots increasingly assigned to non-flying jobs and the lure of lucrative jobs in commercial aviation.

Ultimately, however, it boils down to a reduction in fighter aircraft, which naturally means few fighter pilots (at least in fighter cockpits): 

A 2009 RAND report said that, by 2016, the Air Force will have fewer than 1,000 fighter aircraft in its inventory, which represents only 32 percent of the number in 1989. The Air Force currently has just over 1,900 fighter/attack aircraft in the active, guard and reserve forces, according to Air Force officials.

As has already been noted, the commercial aviation market is expected to be a lucrative enticement for current Air Force pilots.  Combined with an increased ops tempo due to reduced manning, it could provide a retention challenge.

The Stripes article references a letter from USAFE Commander General Mark Welsh, which was previously discussed for its inclusion of the 2009 Dear Boss letter.