Flights for UA1521 These are not all the flights that UA1521 has taken, just some of them that have flown in or out of SFO

UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on June 26, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on June 11, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on June 19, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on July 01, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on July 05, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on June 19, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SEA)
This United Airlines flight traveled from San Francisco International Airport to Tacoma International Airport, on July 02, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.
UAL1521 (SFO-SNA)
This United Airlines flight traveled from San Francisco International Airport to John Wayne Airport, on February 04, 2014. Passengers were flying aboard a Boeing 737-800. See all the flights for UA1521.
UAL1521 (YVR-SFO)
This United Airlines flight traveled from Vancouver International Airport to San Francisco International Airport, on March 25, 2015. Passengers were flying aboard a Boeing 737-900. See all the flights for UA1521.

All these flight data are available as openly licensed data on the sfomuseum-data GitHub account. If you'd like to read more about our efforts to archive flight data at SFO Museum have a look a the Mills Field weblog posts tagged "flightdata".