FILE – In this Sept. 16, 2001, file photo, an American flag flies from a makeshift altar overlooking the ongoing investigation of the United Flight 93 crash site in Shanksville, Pa. Officials announced Friday, June 1, 2018, that later in the year, the National Park Service will return the remaining wreckage of United Flight 93 to the Pennsylvania memorial marking where it crashed in the 9/11 terror attacks, and the remaining wreckage will be buried in a restricted area accessible only to loved ones of the victims. (AP Photo/Gene J. Puskar, File)