I’ve seen it online in a few places, here on IMDB (https://www.imdb.com/title/tt0094012/trivia)…
The escape pod launch sequence is an unused clip from Star Wars: Episode IV - A New Hope (1977), provided to Mel Brooks by Lucasfilm.
There’s no way that’s true.
Comparison:
https://imgur.com/0cm6HoC
The design of the tunnel and pod are only passably similar and share no identical features, though the silly door on the pod and the excessive greebling of the tunnel should be dead giveaways that this was made specifically for Spaceballs.