The B-2A Spirit is the US Air Forces brand new stealth aircraft. It is the most expensive known aircraft, costing in excess of $71 billion dollars for 132 aircraft! That makes it $538 Million dollars a piece! The F-14 costs $30 million. It is no doubt the most controversial aircraft of the 20th century, due to it's cost and the fact that, in light of recent world developments, it may not even be needed for it's main mission, which is to drop nuclear weapons. Although it can carry an array of conventional bombs and missiles.
Using flying wing technology, the B-2A's airframe is 50% more efficient then that of the B-1B. It flies at high subsonic speeds, at altitudes of up to 50,000 feet.
The aircraft's stealthieness comes from it's shape as well as it's coating. Void of all vertical surfaces, the B-2A can deflect radar beams in different directions, so they are never recieved by the radar recieving stations. They are also absorbed into the special coating that covers all parts of the B-2A.