They've been trial ballooning the nonsense "quademic" again, probably testing public receptiveness. I suspect aliens is more of a long-term Hail Mary sort of option, but who knows? They desperately want WW3; that's serious and imminent risk.
Of course as often as I hear Israelis saying countries need another 9/11, maybe it just ends up being something like that. There are other potentialities: there's a financial crisis available if they want to tap it, there's mass hacking events/attacks on the grid or hospital system via hacking (easy to blame on anyone) or sabotage, and there's that outlier where the WEF was discussing a threat to drinking water a few years ago.