Did Biden Secretly Fly 320K Unvetted Migrants to American Airports in 2023?

On March 4, 2024, the claim that the Biden administration had secretly flown 320,000 migrants into the U.S. in 2023 went viral. That claim originated from a report by the Center for Immigration Studies, a conservative think tank. The report, and its assertions, gained significant exposure when the Daily Mail covered it and Elon Musk shared the Daily Mail article on X (formerly known as Twitter). Former U.S. President Donald Trump also repeated the claim in his Super Tuesday victory speech on March 5, 2024.

The central assertions made by CIS, repeated by the Daily Mail or others, were that:

A Biden administration program was responsible for flying 320,000 migrants directly into the United States between January and December 2023. (True)