More turbulence for United Airlines, and this time the troubled carrier has targeted some of our most beloved superheroes.

As the annual Comic-Con wrapped up this weekend, cosplayers and more mildly dressed comics fans were greeted by an unusual sign as they arrived at San Diego's airport to return to their regular lives.

"Comic-Con Attendees: Remove All Books From Checked Bags" read one sign widely shared on social media.

No books in bags? Really? Talked about be stripped of your superpowers and then some.

United's ever-responsive Twitter support team clarified for one passenger that it was in fact just comic books that cannot be checked, as if that somehow makes more sense.

United responded to travelers' confusion publicly on Twitter by passing the buck to the feds, tweeting that "the restriction on checking comic books applies to all airlines operating out of San Diego this weekend and is set by the TSA."

The Transportation Security Administration was having none of this business, however, and proceeded to publicly correct United on the platform.

"Good afternoon. Pls note there are no TSA restrictions on checking comic books or any other types of books," the agency's official account responded to the airline.

As if struggling to come up with any possible explanation for what United might have been thinking, the TSA shared a link debunking rumors that books should be removed from carry-on bags before going through the x-ray at security, but that doesn't explain why anyone would think that comic books in checked bags could be an issue.

I've reached out to United for an explanation and will post an update when I hear back. Until then, United will continue to be a kind of oracle of bizarro corporate management and decision-making.