Several people present at the show recorded the incident on their mobile phones.

The visuals show that the Boeing B-17 bomber was not flying very high from the ground. At the same time, the smaller plane - a Bell P-63 Kingcobra, rushed in its direction from the left and hit the B-17 on top.

Immediately, both planes broke apart into pieces, and, turned into a ball of fire instantly after falling on the ground.

The incident occurred at the Wings Over Dallas Airshow at Dallas Executive Airport.

The US Federal Aviation Administration (FAA) said it would investigate the incident along with the National Transportation Safety Board.

Dallas Mayor Eric Johnson said many details of the incident couldn't be confirmed immediately.

"As many of you have now seen, we have had a terrible tragedy in our city today during an airshow. Many details remain unknown or unconfirmed at this time. The National Transportation Safety Board has taken command of the crash scene with Dallas Police Department and Dallas Fire-Rescue continuing to provide support," he said.

The B-17, a four-engined bomber, played a major role in winning the air war against Germany in World War II, said an AFP report.