The Federal Aviation Administration's chief said in Atlanta Thursday that he's worried that Congress will pass a funding bill "well below" what President Barack Obama proposed for his agency.

"Funding at these levels would degrade the safe and efficient movement of air traffic today and in the future," FAA administrator Randy Babbitt said.

Babbitt's remarks to the Atlanta Aero Club came as the agency awaits funding from Congress. The House and Senate have passed FAA reauthorization bills. But political wrangling has slowed progress on a final version.

House bill supporters say that chamber's version saves $4 billion and requires the FAA to find savings without negatively impacting aviation safety.