President Donald Trump arrives at Wilmington International Airport, Wednesday, Sept. 2, 2020, in Wilmington, N.C. (AP Photo/Evan Vucci)

FILE - In this Sept. 11, 2019, file photo a Pennsylvania State Trooper pauses in front of the Wall of Names at the Flight 93 National Memorial in Shanksville, Pa. before a Service of Remembrance as the nation marks the 18th anniversary of the Sept. 11, 2001 attacks. The Wall of Names honor the 40 people killed in the crash of Flight 93. Both President Donald Trump and Democratic challenger Joe Biden will commemorate the 19th anniversary of the Sept. 11 attacks in rural Pennsylvania where one of the hijacked planes crashed in a field. (AP Photo/Gene J. Puskar, File)

Democratic presidential candidate former Vice President Joe Biden removes his face mask as he arrives to speaks in Wilmington, Del., Wednesday, Sept. 2, 2020, about school reopenings. (AP Photo/Carolyn Kaster)