Six people were dead after two vintage military planes collided midair on Saturday and crashed in flames before a crowd of thousands who came to see them fly at a World War Two commemorative air show in Dallas, officials said on Sunday. No one in the crowd of 4,000 onlookers was hurt, and no names of the victims were released.

“Authorities will continue working today on the investigation & identification of the deceased,” said Judge Clay Jenkins, the chief elected official in the Texas county. “Please pray for their families and all involved.”

The crash involved World War Two-era planes — a Boeing B-17 Flying Fortress bomber and a Bell P-63 Kingcobra fighter — that were flying at the Wings Over Dallas Airshow at Dallas Executive Airport, the Federal Aviation Administration (FAA) said in a statement.

Hank Coates, the president and CEO of the Commemorative Air Force, a group dedicated to the preservation of World War Two combat aircraft, said the B-17, a massive four-engine bomber, normally has a crew of four to five people.

The P-63 is a US fighter plane manned by a single pilot, Coates added, but he would not say how many people were aboard the aircraft at the time of the crash.

Leah Block, the spokesperson for the Commemorative Air Force, which is dedicated to preserving World War Two aircraft and hosts the air show, said told the Fort Worth Star-Telegram that they are not sure why the accident occurred. Officials from the National Transportation Safety Board (NTSB) started an investigation on Sunday.

Two World War II-era planes collided in midair at an air show in Dallas on Saturday, killing at least six people. Around 4,000 people were at the event, meant to educate people about World War II history and honour the contributions of veterans. The planes were a Boeing B-17 Flying Fortress and a Bell P-63 Kingcobra. Paul Martin, a member of the Army Air Forces Historical Association, said the Flying Fortress was a lumbering bomber that was like a “tractor-trailer truck” while the Kingcobra was a single-pilot fighter plane. To have either aircraft in flying condition was a rare occurrence, he said. He said he was aware of only about nine B-17s in flying condition and only one P-63 Kingcobra — before Saturday’s crash. (AP/PTI picture)