According to the FAA, the TCAS is part of the Airborne Collision Avoidance System (ACAS), which is a safety-enhancing system to reduce the chances of mid-air collisions between aircraft.

Without an air traffic control tower, it’s a calculated dance that requires communication by pilots. Two small planes collided in midair over one of the runways on the outskirts of Tucson last week.

Nonetheless, labor and industry groups argue that air traffic control towers were already understaffed, posing risks to aviation safety. As investigations into the Arizona mid-air collision ...