Authorities said the United Airlines plane was preparing to fly from Sea-Tac Airport to Washington, D.C., when it caught fire before takeoff on Saturday night.
The Seattle Times reported the aircraft was evacuated and firefighters extinguished the flames.
No one was hurt as all passengers on United flight 776 were safely evacuated at 10.27pm, Sea-Tac spokesman Perry Cooper said.
The Washington Post said the plane was towed to cargo services for further investigation.
The plane that caught fire came to Sea-Tac from Chicago’s O’Hare International Airport, the airline’s website said.
United’s website indicated that the flight’s passengers were to be put on another plane a couple of hours later.