The head of the Federal Aviation Administration warned that the sequester could lead to major flight delays and the closure of hundreds of air traffic control towers at smaller airports across the country.

"Flights to major cities like New York, Chicago and San Francisco could experience delays, in some instances up to 90 minutes during peak hours, because we'll have fewer controllers on staff," FAA administrator Michael P. Huerta said Wednesday in a speech to an American Bar Association forum in downtown Washington. "And delays in these major airports could ripple across the country."

Most of the agency's nearly 47,000 employees would likely be furloughed one day for each two-week pay period until the fiscal year ends in September, Huerta said.

The FAA may also need to eliminate midnight shifts at more than 60 air traffic control towers, Huerta warned. In addition, the agency could be forced to close many of the 230 air traffic control towers at airports that are less busy, like those in Boca Raton, Fla., and Joplin, Mo.

"The reality is, what we're looking at is a series of bad choices, and what we're trying to do is minimize the impact on the maximum number of travelers," Huerta said.

Huerta echoed the words of Transportation Secretary Ray LaHood, who last week predicted that the sequester would wreak havoc on air travel across the country.

Huerta is testifying Wednesday before the House Appropriations Aviation subcommittee, where he reiterated many of his points. Follow the Post's Ashley Halsey on Twitter for live updates from that hearing.