(a quick physics lesson) In space, if you point your ship in one direction and keep accelerating in that direction, you will go faster, faster, and faster untill you reach light speed. This assumes that you are in a pure vacuum, so there's nothing to stop your acceleration. In reality, You won't have enough fuel to make it all the way to light speed. Also, There would be relativistic effects and some drag from hydrogen and other particles as you get near light speed.
In either case, there's no law of physics that says that WC capsips can't travel at these speeds. With the scoops closed, all WC ships are merely projectiles; and thusly, move the same way real life ships would move if they were built with matter/antimatter drives. The speeds mentioned in End Run are theoretically possible.
Icehart, we do have some control of the scoops in the games. It's called "autosliding", which turns the fighter's scoops on or off.
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Meson
Wing Commander is more than just a game. It is a lifestyle.