The FAA will have to certify SpaceShipTwo as airworthy, but there are as yet no protocols in place for that process.
The law says that it can't leave the ground unless it's airworthy.
This is to notify you that the aircraft in question has been inspected and found to be not airworthy.
The inventor thinks they will be compact and just as airworthy as ocean liners are seaworthy.
Without wings or control surfaces, it is obviously not airworthy.