The president of a union representing federal air traffic controllers said Tuesday the U.S. Federal Aviation Administration (FAA) needs to do a better job of ensuring adequate staffing to oversee the nation's airspace.

Rich Santa, who heads the National Air Traffic Controllers Association, said the FAA had over 15,000 total controllers in 2011, including over 11,750 fully certified controllers, but at the start of 2022 "there were more than 1,000 fewer (certified controllers) and 1,500 fewer total controllers on-board."

Santa said at a speech in Washington "Unfortunately, FAA staffing is not keeping up with attrition.... There should be 1,000 more controllers, not 1,000 fewer, than we had a decade ago."

Acting FAA Administrator Billy Nolen told Reuters last week the FAA "on track to hire 1,000 controllers this year." For 1,500 open positions, the FAA accepted 57,956 applications for review, he added.

Federal air traffic controllers generally work in control towers, approach control facilities, or route centers, and are essential for coordinating aircraft traffic between the nation's airports.

U.S. airlines have placed blame for a significant part of summer travel disruptions impacting tens of thousands of flights on a lack of air traffic control staffing. The FAA said Tuesday "airlines' data show that the vast majority of delays are not due to air traffic controller staffing. Where demand has increased, the FAA is adding additional controllers," it added, while highlighting training backlogs caused by COVID-19.

"Just like during sequestration and the 35-day government shutdown, the pandemic again forced FAA to suspend hiring and temporarily close its training academy. This has negatively affected staffing," Santa said.

Airlines for America, a trade group representing Delta Air Lines, United Airlines, American Airlines and others, said in June air traffic control staffing challenges were disrupting flights even in good weather especially at Jacksonville Air Route Traffic Control Center in Florida, which was "crippling to the entire east coast traffic flows."

Santa said Jacksonville, which handles airspace covering parts of Florida, Georgia, Alabama, South Carolina, and North Carolina needed more staff. The FAA said in May it had agreed to "immediately increase the number of authorized staff at Jacksonville Center."

He said the union and FAA agreed to a Jacksonville Center staffing target of 275 certified controllers but as of last week there were only 205 certified controllers. Those figures do not include 50 current trainees.

Santa said recent delays in Jacksonville Center's airspace were prompted by unprecedented bad weather, significant increase in commercial space launches and airline operational challenges "but FAA staffing challenges are also a piece of this complex puzzle."