Can a disk like object (like UFO's) really fly? UFOs as shown in movies are shown as disk like objects with raised centers that emit some sort of light from bottom. Can such a thing fly?
My very limited knowledge in physics tell me that a disk like object may not be able to maneuver unless it has thrusters on sides and simple light can not be enough to make any object go up in the air.
Is it possible?
 A: Beam propulsion has already been done here on Earth.  :-)  http://en.wikipedia.org/wiki/Beam-powered_propulsion
A: Have a look at the flying car 
There is even a video.
A: The light below a UFO is actually ionized air. A light beam would not be visible by itself. According to some witnesses mentioned by Feindt the ionized air below is rotating, creating a Taylor column, which could explain why the heavy flying saucer shaped vehicle doesn't fall down. According to Hill pulsating forces can be felt near the UFO. One can imagine that the forces mainly propagates in the weak plasma below the saucer. Hill writes that the saucer type of UFOs tilt to turn.
Electromagnetic radiation beam powered propulsion can not be the case since it would loose too much energy to the ground than can be observed. Light and other radiation might be used to affect the plasma though.
Good reads on the physical aspects of UFOs are

Paul R. Hill - Unconventional Flying Objects: A Former NASA Scientist Explains How UFOs Really Work
Carl W. Feindt - UFOs and Water: Physical Effects of UFOs on Water Through Accounts by Eyewitnesses

A credible UFO witness in regard to physical (as well as other) aspects is Billy Meier. His stories, photos and drawings are revealing but also very demanding to understand.
A: In mid 2010, Japan Aerospace Exploration Agency launched IKAROS, a spacecraft that is pushed by the radiation of the Sun.
Explanation: If you consider relativistic effects, light (photons) have no mass, but they can carry momentum $p=h/\lambda$ per photon particle, where $h$ is Planck's constant and $\lambda$ is light's wavelength. So, if UFOs can generate very bright light (very high intensity), theoretically they can push themselves against the gravity.
A: The lift works on the craft body by interaction between the curren on which flows through the body surface and the magnetic field of the body center.　”The law on the left Fleming."
