N328KF in the National Air & Space Museum.
N328KF is the first and only example of Scaled Composites SpaceShipOne suborbital spaceplane. It was built by Scaled Composites ("Scaled"). It won the suborbital spaceflight X-Prize. It requires a mothership, and uses N318SL, the sole example of Scaled Composites WhiteKnightOne built as its mothership.