Virgin Atlantic Global Flyer : Flight Tracker

This morning finds the GlobalFlyer and Steve over North Africa -- Algeria at this moment. I find myself keeping this browser window open most of the time that I'm online. He's really flying high at the moment -- about 47,000 feet. His speed shows 314 knots -- I'm guess that's ground speed but I'm really not sure since the tracker doesn't say. (and for any of you pilot types, I know that's really FL470 which is why I'm guessing about the groundspeed vs. airspeed let alone TAS, IAS, etc. -- gosh I wish they would specify that!)