This is true.
Billboard released an article on February 2nd, 2024, after getting confirmation from Jack Sweeney that he received a cease-and-desist letter from Taylor Swift's attorney last December. The article also explains that Sweeney has been tracking flights for other celebrities such as Kim Kardashian, Bill Gates, and Donald Trump. "He cites publicly-available government flight data, alongside estimates of carbon emissions from each flight."
After looking deeper into the situation, the letter sent to Sweeney, from Swift's lawyers, claims that the information Sweeney shared is a "life or death matter" for their client, Taylor Swift. This is due to increased stalking and personal violation attempts made on Swift in recent years. The letter does not flatly state that Sweeney is the one performing the stalking behavior, instead, it links recent stalking behavior to the jet information that Sweeney draws attention to. The letter states, "You essentially provide individuals intent on physically harming her, or with nefarious or violent intentions, a roadmap to carry out their plans." Sweeney's lawyer released another public statement calling the claims made by Swift's attorney unfounded and hyperbolic.
I also looked into other articles about the same topic, and they all confirm that Sweeney received a cease-and-desist from Swift's legal team. I've linked these articles below with the Billboard article. I also confirmed that Sweeney is a student by reading an article posted by BBC, which states that Sweeney is currently a third-year University student at the University of Central Florida where he is working to get an information technology degree. https://www.bbc.com/news/world-us-canada-68248168
https://www.billboard.com/business/legal/taylor-swift-private-jet-tracker-threatened-lawsuit-1235600528/
https://www.harpersbazaar.com/celebrity/latest/a46670942/every-detail-taylor-swift-private-jet-legal-case/
https://www.washingtonpost.com/technology/2024/02/06/taylor-swift-jet-tracking-legal-threat/
https://www.rollingstone.com/music/music-news/taylor-swifts-lawyers-threaten-student-private-jet-tracker-1234962228/
https://www.theguardian.com/music/2024/feb/06/taylor-swift-jet-cease-desist-jack-sweeney