Nationwide, the inspector general warned, the FAA should be able to maintain staffing levels but not the experience quotient, concluding that the agency "faces an increasing risk of not having enough fully certified controllers in its workforce."

FAA juggles new system with old needs The FAA is in the early stages of a long-term plan to move many of its traffic control operations from ground-based radar to a satellite tracking system dubbed Next Generation, or NextGen.

Radar signals become less reliable over longer distances, which means controllers have to keep planes at the same altitude at least 5 miles apart for safety. NextGen is designed to take much of the physical tracking of flights off the shoulders of controllers, exploiting the accuracy of satellite positioning to allow planes to fly nearer each other, thereby cutting delays and cancellations.

"You fly closer together, both vertically and horizontally," said Headley, co-author of the annual aviation ratings. "You have more direct flights. You save fuel. You save time. Everything's simpler."

NextGen is a sprawling program involving billions of dollars in federal-private cooperative ventures, research, software development and workforce upheavals, and after four years, it remains largely in the planning stages.

In a report to Congress in March, the Transportation Department said the FAA had fallen behind on laying out clear priorities for NextGen. In May, Congress approved a multi-year FAA funding bill that significantly increases NextGen resources and oversight.

Jones of the FAA said the agency was already "taking incremental steps now that will lead us to full implementation" of the NextGen system and that "at some airports, we are using procedures and technology that are helping us gain efficiency right now."