By David Shepardson WASHINGTON (Reuters) -A bipartisan group of three U.S. senators on Tuesday called for new funding to boost air traffic control staffing, speed training of new controllers and provide new incentives to retain aviation workers.

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.