Jack Sweeney uses publicly available data to track the take-offs and landings of planes belonging to the wealthy and posts them one day later.
The tracking amounts to “stalking”, Swift’s lawyers claim.
In 2022, Twitter banned Mr Sweeney after Elon Musk accused him of sharing his “assassination coordinates”.
Swift’s lawyers have issued a cease-and-desist letter to Mr Sweeney, a 21-year-old student at the University of Central Florida, demanding that he stop sharing the location of her private jet.
The letter, issued in December, says that the information poses “an imminent threat to the safety and wellbeing” of Swift, calling it a “life-or-death matter” for her.