The stupid take is the one you propose, it's ridiculous. So USAF has secret decoys in WWII and before, that followed WWII fighters, and hovered over people's houses, among millions of other sightings worldwide? So advanced yet they don't send them to war?
The energy required for some UFO manoeuvres is far above what we know how to create: https://youtu.be/HlYwktOj75A?si=Q68f2ODxgO_IpGlv&t=770
You're falling in the same trap as conspiracy theorists, though: Putting out almost non-falsifiable statements, and then claiming you know better and are smarter. Either it will be revealed that it was USAF and you can feel smug about being correct, or it will not come out and you can still feel smug about being correct because no one can prove you wrong.