The Washington Post reports:
President Biden and first lady Jill Biden are scheduled to travel to three locations, starting with New York City, then moving on to Shanksville, Pa., and finally Arlington, Va.
Their day begins at Ground Zero in New York City for a ceremony that begins at 8:30 a.m. At 8:46 a.m. they will hold a moment of silence, 20 years to the minute after the first plane, American Airlines Flight 11, crashed into the North Tower of the World Trade Center.
At 12:30 p.m. the president and first lady will attend a wreath-laying ceremony at the Flight 93 National Memorial in Shanksville. They will later attend, shortly before 5 p.m., a ceremony at the Pentagon in Arlington.