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.

Chatter over the airwaves has provided some clues about what happened in Arizona. A chief flight instructor who was in the air with a student that day heard the commotion over the radio: One plane was attempting a touch-and-go when another clipped its propeller while attempting to land.

It's safe to say that America has an air traffic control problem. A lengthy string of near-misses culminated in the worst possible outcome last month: a fatal mid-air collision between a regional jet and a military helicopter at Reagan National Airport.

The Trump administration has defended its cuts at the Federal Aviation Administration by saying safety-critical employees weren't affected. Experts disagree.

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.