Dallas Air Show Victims Named; NTSB Investigation Underway

A tragic crash at a Dallas air show resulted in six fatalities when two World War Two planes collided midair. The incident was captured on cell phone videos, showing a massive fire and smoke. The NTSB is conducting a thorough investigation to determine the cause, focusing on why the planes were at the same altitude. The absence of black boxes complicates the investigation.

What factors are being considered to determine the probable cause of the crash?

What will make the investigation more difficult according to the NTSB?