I've always assumed that the stars with the black background was like polka-dot or something. Meaning, in a fashion sense, Lone Starr had "gone to polka-dot" while the spaceballs had "gone to plaid".
That's my take on it, anyway. I don't know
shrug
Mischief. Mayhem. Soap.

in many scifi movies, when a ship is moving at lightspeed (or warp in star trek), there's a striped pattern behind them. and in several star trek movies, this striped pattern is even rainbow colored. going plaid is just going so much faster that your stripes turn plaid instead.

I always thought it was a reference to the freaky light-sequence at the end of 2001: A Space Odyssey. (Apparently, according to wikipedia, that's known as "the Stargate Sequence", but all I remember is a long period of bizarre colored lights and patterns, courtesy of Kubrick).

You knuckleheads. I always took this as a sight gag, not a speed thing. In every film that has time travel there is always a great visual when someone goes into hyperspace or light speed. Star trek has lines and lights when they go to warp and such.

And polka dot speed, well, the amount of force required for that would shred the fabric of the universe

Now, paisley speed on the other handpaisley speed we do not speak oftoo darned fast

Lighten up, Francis!

Plaid is the design it has while moving at ludicrous speed

Y'knowthe way you explained itI finally get it!

You don't get it?
When you see the ships go into hyperspace you see a bunch of lines, correct?
Lines or -
stripes
! The screen is filled with
stripes
.
Stripes are common in fashion
(even today)
. So of course, what's one step from stripes but plaid? So you see a bunch of stripes first, and then it goes to plaid.
I suppose after that you could go paisley, whatever is after ludicrous speed.
Plus, a common fashion faux pas
(think old Jewish guy on the golf course in the 80's here)
is to wear plaid with stripes.
It's always been one of my favorite scenes in the movie, but I was already in my late 20's when it came out.

I always saw it as a parody of the 'Jupiter and Beyond the Infinite' part of 2001 a Space Odyssey when Bowman is sucked through a tunnel of coloured lights used to imply great speed. Rather than just random patterns Mel Brooks made it plaid.

Austinmey is right.
In Star Wars, the stars ''become''
lines
when a ship enters the lightspeed.
But with plaid, you have lines everywhere, indicating that it's a lot faster and weirder than lightspeed.

Hm, hom!

Hey, that wasn't half bad!
I always just kind of accepted the 'not supposed to make sense'-thing, but light speed = straight lines vs. plaid = angles thing actually makes sense (out of the senselessness).

Plaid* not plan

Is this not a reference to Star Wars as well? Being that light speed is straight lines and going to plan it's just a bunch of right angles and plaid patterns.
I don't know, but it's my favorite joke in the entire film.

Maybe Snotty was responsible.

Agree, it's just the absurdity of it.
I don't know if you're aware of this but I've already changed things. I killed Ben Linus.
Sayid

I agree with youit made no sense to me when I saw it the first time and still makes zero sense. I am glad I am not the only one!! I totally don't see the connection.

This is a discussion board and the OP asked specifically what the humor in this was. What's your problem?

Thanks for over analyzing a gag about the distortion of light left by going ludicrous speed. You earn the nerd award
Panzer vor!

Still doesn't make sense - I mean, for that joke they already invented "ludicrous speed".
To make things even more confusing, I watche Spaceballs with german dubbing and they didn't even translate "plaid".
HOWEVER, reading the quote section I've got a hint when reading the actual quote:
Barf: [Spaceball 1 roars by them,
in a plaid colouration of speed]
Aah!
Barf: What the hell was that?
Lonestar: Spaceball 1.
Barf: They've gone to plaid!
So, plaid seems to refer to the colour pattern that is shown in the movie when you see a sapcehip move at ludicrous speed. So it's actually a meta-joke becaue in reality there would be no colour pattern and even there was, it would move too fast to be seen.

There is no connection. Speed of light is generally regarded as the speed limit of the universe: nothing can move faster.
The writers decided they would come up with something that would be faster, and went for absurdity. 'What's faster than speed of light? Plaid."
It's not supposed to make sense.
What sort of a man doesn't carry a trowel?

Sorry to say, I think you'll have to accept the explanations given.

Sorry to say, I'm still not making a connection between light and plaid. I really think I need it spelled out for me.

What's faster than "light" speed?
Plaid