We are more likely to come into contact with UFOs powered and navigated by artificial intelligience (as compared to biological lifeforms) as they are more likely to be able to survive the harsh and long periods of space travel. For us (with our current technology) to travel to the nearest Alpha Centuri system, the travel time would already exceed our biological life expectancy. http://earthsky.org/space/alpha-centauri-travel-time Chemical rocket fuel is too inefficient. A solar sail could solve the problem of carrying fuel weight and reach Alpha Centauri in about 45 years.
The UFOS of many eyewitness reports are able to more at breakneck speeds and change flight paths astoundingly quick. If there were biological lifeforms piloting this, they must be wearing a suit that can counter the crushing G force that would otherwise kill the pilot.
Saucer-shaped aerial craft do not do well for manuverability in earth's atmosphere as compared to the Delta wing design.
Another common description about UFO is that they are quiet, sometimes even silent. UFOs would then need to have sound-cancelling technology that could cancel out the effects of a sonic boom (caused by the pressure difference between the front and back of the aircraft).
Another common description about UFO is that they are quiet, sometimes even silent. UFOs would then need to have sound-cancelling technology that could cancel out the effects of a sonic boom (caused by the pressure difference between the front and back of the aircraft).
