Epistemic status: Big if true/I am clearly an idiot for even posting this.
Some apparently real journalists have been approached by (& approached) several intelligence officials, some tasked specifically with investigating UFOs, who claim that the DoD has had evidence of alien intervention for a while in the form of partial & mostly-whole fragments of alien aircraft. A followup article where the publication outlines how the editors verified this persons' and others' claims and affiliations is here, and a part 2 is expected tomorrow.
For some reason - very possibly because it's complete nonsense, or because they haven't had time to independently verify - the story has only been picked up by NYMag so far. The consensus among the people I've been reviewing this article with, is that it's either a complete hoax (i.e., the entire thing nearly top to bottom is some deliberate deception) or there's a non-negligible (>5%) chance aliens are here. I would love for someone who has a good understanding of the material to give an explanation (including possibly on priors, just thinking clearly about the content of the article) of why my friend group should discount this out of hand.
Thus far I have been unconvinced by most stories of why we should to-the-point-of-not-caring-about-UFO-sightings-expect Aliens have to be big and obvious and tile the universe with fun, as opposed to operating some sort of noninterventionist monitored lightcone.
Press X to doubt. First, the details on flying saucer fragments have not been disclosed (as far as we know), so this strategy was not attempted. Second, though this is not a knockdown argument given that we're dealing with the U.S. government, it would be an incredibly dumb strategy to build a new jet and then claim it's a UFO in order to trick the Chinese government into thinking you're not running missions in their airspace. The Chinese might not know about it, and the chances that the equipment you possess are U.S. made are higher from the Chinese perspective than if you had said nothing. It strikes me as conspiratorial thinking that the intel community would disclose its own equipment to the world, with such a preposterous explanation, as a sort of "feint".