An unoccupied Ethiopian Airlines 787 Dreamliner caught fire while parked at London's Heathrow Airport, reprising worries over the Boeing Co. flagship jet three months after it resolved battery problems that had grounded it worldwide.

Emergency crews were called about 4:30 p.m. local time on Friday and soon extinguished the blaze. No one was injured in the incident, which prompted airport authorities to halt flights for more than an hour at Heathrow, the world's busiest international airport. Broadcast images showed that the...