What is Flight?

Legal Definition
Flight is the process by which an object moves, through an atmosphere (the air in the case of earth) or beyond it (as in the case of spaceflight) without direct support from any surface. This can be achieved by generating aerodynamic lift, propulsive thrust, aerostatically using buoyancy, or by ballistic movement.

Many things fly, from natural aviators such as birds, bats and insects to human inventions such as missiles, aircraft such as airplanes, helicopters and balloons, to rockets such as spacecraft.

The engineering aspects of flight are studied in aerospace engineering which is subdivided into aeronautics, the study of vehicles that travel through the air, and astronautics, the study of vehicles that travel through space, and in ballistics, the study of the flight of projectiles.
-- Wikipedia
Legal Definition
Crim. law. The evading the course of justice, by a man's voluntarily withdrawing himself. 4 Bl. Com. 387. Vide Fugitive from justice.
-- Bouviers Law Dictionary
Legal Definition
In criminal law. The act of one under acousation, who evades the law by voluntarily withdrawing himself. It is presumptive evidence of guilt. U. S. v. Candler (D. 0.) 65 Fed. 312.
-- Black's Law Dictionary
Legal Definition
Fleeing to avoid arrest for crime.
-- Ballentine's Law Dictionary