Six people are dead after two World War II-era military planes collided in midair and crashed at Dallas Executive Airport during an airshow Saturday afternoon, killing all on board, the Dallas County Medical Examiner’s office said Sunday.

“We can confirm that there are six (fatalities),” a spokesperson for the Dallas County Medical Examiner’s office told CNN in a phone call.

More than 40 fire rescue units responded to the scene after the two vintage planes – a Boeing B-17 Flying Fortress and a Bell P-63 Kingcobra – went down during the Wings Over Dallas airshow.