After 2010, the only spaceplane in the U.S. inventory will be the Air
Force's
mysterious X-37.


See:

http://www.airspacemag.com/space-exp...tml?c=y&page=1

Quote:

"the X-37 has taken a winding and perplexing path among NASA, DARPA,
and the Air Force.
From 2004 to 2006, DARPA oversaw it. Along the way, both the X-40A and
the X-37A have
been drop-tested (first over New Mexico in 1998 and California in
2006, respectively), which
proved their automated approach and landing abilities. Finally the
program was taken over by
the Air Force. Today, call up any of these organizations and say
"X-37" and it's like spraying
a garden hose at housecats."