A World War II-era plane crashed at Hartford airport, Connecticut, US, after takeoff on Wednesday, killing seven of the 13 people on board.

The B-17 bomber struggled to get into the air and crashed into a maintenance building as the pilots went back for a landing, officials and witnesses said.

It had 10 passengers and three crew members, authorities said.

Connecticut Public Safety Commissioner James Rovella said hours after the crash that some of those on board were burned, and "the victims are very difficult to identify".

Some of the survivors of the crash were critically injured, authorities said. One person on the ground was also hurt in the crash and a firefighter suffered a minor injury. No children were on the plane.

The death toll of seven could rise, Rovella said. He said some lives were likely saved by the efforts of people including a person who raced to help the victims and people on the plane who helped others to escape the fire by opening a hatch, Rovella said.

"You're going to hear about some heroic efforts from some of the individuals that were in and around that plane," he said.


The vintage bomber - also known as a Flying Fortress, one of the most celebrated Allied planes of World War II - was used to take history buffs and aircraft enthusiasts on short flights, during which they could get up and walk around the plane.