"We can confirm that there are six (fatalities)," a spokesperson for the Dallas County Medical Examiner's office confirmed.

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.

In video footage of the crash that was described by Dallas' mayor as "heartbreaking," the planes are seen breaking apart in midair after the collision, then hitting the ground within seconds, before bursting into flames.