Not much to go on here but something brought it to mind and it’s driving me nuts.
I’m not sure when the movie was made but strongly suspect the 1960s. I believe it was color and not B & W.
It was a science fiction movie that was done as a satire on the type. The base premise was an alien invasion that takes place largely off-screen. The distinguishing characteristic was a reference to a science fiction TV show. Some janitor or something has worked his way up to some exalted rank by sending in box tops and learning the secret code. He is then joined by people of increasing importance in the real world but with decreasing rank in the fan club and they follow him. Ultimately a general in the army, who is but a lowly private in the “space cadets” (or whatever they were called) joins his band.
I think that, under the janitor’s leadership, they end up repelling the invasion somehow, but that is merely a vague recollection.
Did it have some really artsy shots? One was a woman in a full shirt standing in the middle of a road at sunset.
If so, I can’t help you, because I’ve had the same question for a while…
Good luck.
If it’s the one that’s been driving me crazy, it was much more subtle than those. There was a feel of '50s B movie space operas. (The Blob; I was a Teenage Werewolf)