Donald Peterson

Of the 33 passengers (excluding the four hijackers) who are on board Flight 93 on September 11, at least 16 are not originally booked on this flight, but arrange to be on it very shortly before 9/11, or—in some cases—on the morning of 9/11 itself:
Environmental lawyer Alan Beaven arranges to take Flight 93 to San Francisco the day before 9/11, as he is duty-bound to go there to help settle a case after talks have just broken down. [San Francisco Chronicle, 9/17/2001; Sacramento Bee, 9/30/2001]
Todd Beamer would normally have flown the night of September 10, as he has a business meeting scheduled for later in the day of 9/11. But he delays his flight, as he wants some time with his children after returning from a trip to Italy. [Pittsburgh Post-Gazette, 10/28/2001; MSNBC, 9/11/2006] He usually flies Continental Airlines, but chooses United to save his company money. [Longman, 2002, pp. 18]
Edward Felt also usually flies Continental Airlines, but books himself onto Flight 93 at the last minute after his company gives him short notice of a meeting he needs to attend in San Francisco. [New Jersey Star-Ledger, 9/15/2001; Longman, 2002, pp. 194]
Mark Bingham should be flying on September 10, but delays his flight as he has a hangover after a friend’s birthday party. [San Francisco Chronicle, 9/17/2001; Newsweek, 9/26/2001]
Deora Bodley is originally scheduled to fly from Newark to San Francisco on September 11 on United Airlines Flight 91. [Sacramento Bee, 9/14/2001] She decides on the night of September 10 to switch to Flight 93, as its departure time is more than an hour earlier. [San Francisco Chronicle, 9/17/2001; Pittsburgh Post-Gazette, 10/28/2001]
Lauren Grandcolas is booked on Flight 91, but on September 11 arrives early at the airport and switches to Flight 93. [Longman, 2002, pp. 12; MSNBC, 9/11/2006]
Husband and wife Donald and Jean Peterson are booked on Flight 91, but also arrive early and switch to Flight 93. [Pittsburgh Post-Gazette, 10/28/2001; Longman, 2002, pp. 13 and 16]
Christine Snyder calls the airport early in the morning of September 11 and transfers from Flight 91 to Flight 93 for an earlier start. [Pittsburgh Post-Gazette, 10/28/2001]
Tom Burnett is scheduled for a later flight, but switches to Flight 93 to get home earlier. [Knight Ridder, 9/14/2001] According to journalist and author Jere Longman, he too is originally booked on Flight 91. [Longman, 2002, pp. 8] But the San Francisco Chronicle says he is originally booked on a Delta Airlines flight in the afternoon of 9/11. [San Francisco Chronicle, 9/17/2001]
Georgine Corrigan switches flights when she checks in at the airport early in the morning of 9/11, so as to get home sooner; her original plane would make two stops on the way to San Francisco, but Flight 93 is non-stop. [Longman, 2002, pp. 12; Associated Press, 9/9/2006]
Jeremy Glick should be on a flight the night of September 10. According to some accounts there are problems due to a fire at Newark Airport. [Dallas Morning News, 9/17/2001] The flight is rerouted to JFK Airport in New York and is due to arrive in California at 3:00 a.m., which does not suit Glick. [MSNBC, 9/11/2006] But according to Newsweek, Glick is originally due to take Flight 93 on September 10, but misses it after getting stuck in traffic on the way to the airport. [Newsweek, 9/22/2001]
Nicole Miller’s original flight the night of September 10 is canceled due to a thunderstorm. [Saratoga News, 9/26/2001; Longman, 2002, pp. 55] She is then unable to get a seat on the same flight as her close friend Ryan Brown, as this is full, so takes Flight 93 instead. [Topeka Capital-Journal, 10/20/2002; MSNBC, 9/11/2006]
Toy-company executive Lou Nacke is called by his boss the evening of September 10 and told to take the first plane to San Francisco, in order to help a customer. [Newsweek, 9/26/2001; Longman, 2002, pp. 124]
In the few days prior to September 11, sisters-in-law Patricia Cushing and Jane Folger move forward the time of their flight. [Longman, 2002, pp. 33 and 35]
Flight 93’s pilot is not originally meant to be flying on September 11 (see Shortly Before September 11, 2001), and at least three of the flight attendants are also assigned to Flight 93 at a late date (see Shortly Before September 11, 2001). The 37 passengers (including the four hijackers) that are on board constitute just 20 percent of the plane’s passenger capacity of 182. [9/11 Commission, 8/26/2004, pp. 36]