Continuity mistake: As the shaving guard falls, he gets shaving cream on Lonestar's right jacket arm. In the next shot Lonestar reaches down to grab the badge and that same arm comes into view and it is completely clean. There isn't enough time between shots for him to have wiped it off.
Continuity mistake: When Dark Helmet takes the ring from Lonestar, he throws down into a grate. Later, when Megamaid explodes and Lonestar and company cheer, for a brief second, you can see the ring back on his finger.
Continuity mistake: When Lone Starr 'knocks out' the guard who was shaving, the guard's grey key card falls to his side, but in the next shot the key card is laying on his butt. (01:11:50)
Answer: Its a reference to how the stars streak around the ships in "Star Wars". "Ludicrous speed" had to have a ludicrous color. It is also referencing 2001: A Space Odyssey, where this "tartan" effect occurs when Dave is in the pod towards the end of the film.
Grumpy Scot
Those answers are quite correct and possible, but how about this: Warp and weft are the two directions of yarn in weaving (of plaids and other things). It might be a very meta joke since plaid is at much higher level than warp. On the other hand, it's Mel Brooks. On the gripping hand, he was born in Brooklyn in the mid 20's and might have been exposed to the basics and vocabulary of the tailor at a young age.
Btw, it's also a clear reference to the sentence from Star Trek "They've gone to warp."