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.

The midair collision at Marana Regional Airport raises questions about air traffic control systems at tower-less airports.

At least two people have died after two small single-engine planes collided midair Wednesday morning at an Arizona airport, officials said.

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.