Electromagnetism is right. All matter contains electrostatic charges, and in fact, are made up of electric points, which are composed of miniture electric fields, which compose atoms, which compose molecules, and so on.
Im going to somewhat explain to you the inner mechanisms of the "pretend" flying saucer. Indeed, it is relatively simple, but naturally it may be hard for you to believe: A) that flying saucers synthesize momentum B) that they are even real C) That I happen to know how they work.
Tesla coils are put onboard and attached to the metal hull of the ship. The reason many saucers glow in the sky are because they are charged with high voltage electricity. When flying saucers move slowly, they put off a light glow that can range from purple to orange to green, this is because the air around them gets ionized from the high voltage currents and behaves much as a flourescent light, the colors can be effected by the power output, as well as the % amount of different gases in the surrounding air. At high speeds they can glow bright blue, bright white, but is not limited to that. In the day time, if you saw one on the ground you would never suspect it was a flying machine, because it wouldn't be your typical flying machine, without( as Tesla said) Ailerons, propellers, or even wings.
If you want to know the nitty gritty: Tune one Tesla Coil to 1/4 frequency on one end of the ship, tune a separate Tesla Coil to 1/2 or 1/1 frequency on the other side(inside) of the ship. Flip the power on, and away she goes.
I'm no alien, but the PEOPLE who currently own these "pretend" space ships have values which are alien to me, because they would rather see you and the rest of humanity as slaves, rather than free and independent humans. That's a large chunk to chew, keep an eye to the sky, filter out lies and trash, turn off your TV, open up a book.
(click on this link to read the book which will explain to you the flying saucer and its inner technologies.)
Good luck.