Do more U.S. airports need control towers? That's one of the questions that has arisen following a midair collision at an airport in southern Arizona last week.

As investigations into the Arizona mid-air collision continue, debates over air traffic safety, regulation, and infrastructure modernization remain front and center.

Tens of thousands of planes take off, land and perform touch-and-goes at the Marana Regional Airport in southern Arizona every year. Without an air traffic control tower, it's a calculated dance that requires communication by pilots.