Birds is use they wing to keep them up. They flap and up in air.
By moving their wings in a flapping motion, along with angling their bodies and internally measuring their speed, they are able to maintain a constant elevation. Some birds travel in V forms to ease the burden on the bird behind them, constantly swapping positions to keep any one bird from having a harder time than another.
Air -- without air they would not fly (besides dieing).
Gravity
You don't specifically need a magnet to overcome the force of gravity; ANY force that is stronger than gravity can "overcome" it, at least temporarily. For example, if you lift an object up, you are "overcoming" the force of gravity.
gravity
gravity
Gravity
hovercraft
Moving Speed, once the rocket is even moving 0.00000001 mph it is overcoming the force of gravity.
The given phrase has little meaning. But levitation by a magnet can overcome the force of gravity.
It travels as a liquid, in response to gravity and obstructions, until friction or solidification overcome the force of gravity.
The upward force would have to overcome gravity, so the force should be F > -mg. Since the upward force and gravity work in opposite direction you can disregard the mass of the object (they cancel: F(gravity) = F(upward) => mg = -m(g+x)) . Consequently the object's mass is irrelevant.
Alright, it is mainly the force of gravity. This is because if there was no gravity, you do not heat energy to fire the rocket up.
Rockets use thrust to overcome the force of Earth's gravity.