According to physicist "Townsend Browns" discoveries he and Einsteins colleague "Biefield" patented a propulsion system known by science and especially the USAF since 1945 is: Biefield Brown Effect. Check it out.
http://www.soteria.com/brown/His method causes NO sound barrier phenomena during flight at any speed. Its part of the mechanics.
Incidently, his 1950's patent on a single wing aircraft such as the B2 bomber and stealth fighter have many things admitted by the AF as to its flight properties that are nearly exactly from his patents. For one, the GE engines I agree with others are not so much for producing thrust as typical jet engines but to function as a sort of hybrid. Mainly as his patent specifies - a HV generator.
The AF admits the following about their stealths. 1) They dump high negatively chgd ions into the exhaust. A known fact when High neg charged particles are dumped into the exhaust trail is it cools rapidly reducing thermal radiation. 2) A leading edge electrode is buried under the forward wings. Admitted by the AF. This dampens the air in front of the craft causing air to be pushed away, minimizing sound. Walla, no crack of the sound barrier.
Another interesting thing is with the enormous electric charge around the craft, (ie. its cloaking ability) the crafts body is an exotic dielectric material, again openely admitted by the AF. Such composites weren't available probably until 80's. Such an intense DC charge across the craft naturally makes it invisible to radar, not so much because of its odd shape or material its composed of but by virtue of the E-field around it. It even generates a thrust and at supersonic speeds the fuel to the engines can be compeletly shut off and fly by the Biefield Brown Effect - completely invisible to standard radar. Quite unstable I might think too without computers. Probably why it flys so ackward, with all the bobbing etc.....
A field can be made so intense that space warps around it, bending light. Giving you the illusion it disappeared in thin air.
Or a craft can simply move with an accelleration so fast, that with the naked eye and the frames per second you can assimilate would appear to vanish and move from position to position as if it were teleporting...It would in reality be moving so fast and stopping on a dime that it appeared relative to the observer as doing this. Inertia, inside the craft would have relativisitic state so the occupants would not be slammed into the wall with a sudden stop or quick 90degree turn. This was proven by Townsend Brown to the United States AF in the 1950's. Ever since, its been classified or circulated as myth and conspiracy theories like UFOs
are. But interestingly it wasn't till 1950's and latter that UFO's really took off as gossip and in sightings. Thats because thats when they really started mass producing the concepts in various ways and shapes in my opinion. Townsed Browns method in my opinion is an old method which can be done in a great number of ways but there are others.
So the next time you see a stealth. Just think, it may be our first hybrid. Jet engines that give it the appearance and flight characteristics of normal jet aircraft, while it employs other neat things too from Townsend Browns - Biefield Brown concept.