I believe the Phillidelphia experiment was an early attempt at stealth technology. It involved the creation of a huge electromagnetic field.

Time travel may not be possible as depected in popular movies, however, time is by no means a constant. Experiments have proven this to be true.

Two identical atomic clocks, one on the ground at an airport, the other placed on a 747. When the 747 was flown around the world and returned to the airport, a several second difference between the two clocks was found. Time on the airplane passed more slowly then at the airport.

This may not have any implications regarding the ability to go into the past or the future, but does have important implications regardind space travel.