The WWII-era P-51 Mustang fighter plane crashed at the National Championship Air Races at Reno-Stead Airport, spraying shrapnel everywhere. Authorities said 70 people were treated at hospitals, and four remained in critical condition.
Among those killed was the 74-year-old pilot, veteran Hollywood stunt pilot Jimmy Leeward. Officials released the names of two people who died: Regina Bynum, 53, of San Angelo, Texas and Sharon Stewart, 47, of Reno. Officials have yet to identify three of the dead.
The National Transportation Safety Board is still trying to find out what caused the experienced pilot to crash.
Investigators said they were analyzing "tremendous amounts of material," including photos that showed a piece of the tail wing missing before the plane hit the ground.
"There are a lot of photos of specific aspects of the tail," said NTSB member Mark Rosekind. "We have found in the wreckage some parts of tail from the accident aircraft. We have those photos."
Four pilots have been killed this year in air shows, but until Friday, there hadn't been a spectator killed at an air show or race since the 1950s.
The Associated Press contributed to this report.