The tragedy, under investigation by federal agencies, involved a single-pilot Bell P-63 Kingcobra crashing into a larger Boeing B-17 Flying Fortress.
"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.
The P-63 is 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.
Video clips posted on social media showed the two aircraft colliding and crashing on the ground, engulfed by flames. Scenes from live aerial video showed debris from the aircrafts scattered on a patch of scorched grass.
Both the FAA and the National Transportation Safety Board (NTSB) launched investigations.
