Maybe here is a more real world explanation:

Imagine Plane on a river, traveling upstream, the engines have to overcome the speed of the relative resistance of the pontoons to the river flow. The only thing to stop it from taking off is the friction of the water acting on the pontoons. The plane would still be able to take off as it's airspeed increases the wings will create more lift, thereby reducing drag and friction until the plane has taken off completely.

Timmah!

And in a vacuum, without influence of air or objects the bullet fired from a gun with a trajectory parallel to the ground and one dropped in the same instance would hit the ground at the same time. Newton's law of Universal Gravitation. Both bullets will still be falling at the measured gravitational acceleration at the Earth's surface, about 980 cm/second/second. Linky

Interesting reading, kinda forgot all that stuff.