Several years ago I got a call from a buddy who was sitting in his outdoor hot tub. He asked me to go outside & look up. After my eyes adjusted I could see hundreds of boomerang shaped objects high up in the sky all travelling westward. So I messaged a fellow pilot who's husband worked at ZAB at the time & asked for his intel. He reported there was nothing from the ZAB "special desk" (whatever that is) except some mil training a hundred miles or so to the NW. My wife & I watched the flight of unknowns for some time, probably 30-40 minutes until clouds obscured the night sky.
I know what we saw that night was nothing like I've ever seen before. There's been too many other credible observations of UFOs, including one by a CA I knew well & flew with on the B757. Much later, his FO was on our j/s & also gave a detailed account of that encounter which also had a momentary ATC radar return, IIRC.
I don't think it's necessarily been a coordinated plan outside of NATO member nations, but do believe various governments have all been sitting on this info.