Ubuweb seems to have the best collection of films by experimental filmmaker Stan VanDerBeek (1927–1984) but not the one I was looking for, unfortunately, an abstract thing entitled Moirage. Searching around turned up Science Friction (1959), one of a number of collage animations VanDerBeek made in the 1950s. The juxtapositions of collage have always been good for comedy, and here they’re put to satirical effect in a comment on the Space Race and the tensions of the Cold War. When viewed today it’s impossible to ignore the resemblance to the later collage animation of Terry Gilliam. VanDerBeek wasn’t the only person doing this at the time—Walerian Borowczyk and Harry Smith also made collage films—but VanDerBeek’s sense of humour seems close enough to Gilliam’s to have given him ideas.
For more about the director there’s also Project Stan VanDerBeek.