At 4:20 p.m. local time, Mirza was scheduled to board the BA 284 flight from San Francisco International Airport to London Heathrow. According to FlightAware, the planned flight was eventually canceled.
“Our thoughts and condolences are with the family and friends of our colleague at this difficult time,” British Airways’ statement to PEOPLE reads.
The cause of Mirza’s passing has not yet been revealed.
