It doesn't yet, but here's a breakdown of how it would work if somebody had bothered to implement it:
- Aircraft normally move at cruising speed. This goes for both UFOs and PHALANX craft.
- When on an intercept course, the intercepting craft or UFO will go into max speed once close enough to the enemy.
- When fleeing an engagement, the fleeing craft will also move at max speed, and will keep doing so until it is a sufficient distance from its pursuers. This distance is greater than the one attacking craft use for max speed.