It is a space bomber. With this type of system the United States can put ordinance anywhere on the planet within minutes.
First let me say I have no inside information or knowledge about this system. I am not affiliated with any organization nor do I have a relationship with any person in any organization that is working on this project (not revealing secrets from anyone with knowledge of the program) or that has information about this system. I deduced this by looking at the system's general capabilities over alternative systems which could accomplish other missions with existing technology with a shorter delivery and more cheaply.
Reentry can be accomplished for unmanned systems by using many of the proven available reentry systems like parachutes which were used during Apollo. Nothing this system can do along the lines of putting something into orbit and bringing it back is necessary unless you need to do it fast.
The same is true for doing things in space. Maneuvering in space is accomplished using countervailing thrust (Newtons equal and opposite reaction) not resistance. You don't need wings for that job and in fact having wings decreases the usable physical space in the payload bay of any launch vehicle. Which leaves us pondering why would you need to put something into orbit and bring it down to Earth differently than what is currently available and has military applications?
This system will give the U.S. military the ability to put ordnance on target extremely fast (hypersonic speeds) if it was in continuous orbit. It is an unmanned bomber that could take out say Ahmadinejad (love to see that %$&^* go) while he is giving a long speech (he loves to talk and talk and talk, you get the idea). Once we have actionable intelligence which could come from say real-time satellite surveillance the target could be eliminated within minutes of the decision being made.
This is magnitudes better than today's current technology which requires hours even with a system in theater. Because of the speed this system would have from reentry it would also be impossible to stop with current technology (even ours let alone theirs). Because it is over target for only a fraction of the time of other systems it would also give us a way to take out high value targets with plausible deniability. The system would enter and leave the target area at high speed at an angle (along with stealth probably) that would make it undetectable and even if a system failure occurred at those speeds it would burn up in the atmosphere which it would do outside the target area (it would look like a meteor.
There are other uses I'm sure, but this would be my guess of its main mission.