Some 13,000 air traffic controllers are being asked to work during the government shutdown, but are not being paid.

Some 13,000 air traffic controllers are being asked to work during the government shutdown, but are not being paid.

The Federal Aviation Administration said staffing was a major cause of flight delays this weekend, though the shutdown ties aren't clear.

Some 13,000 air traffic controllers are being asked to work during the government shutdown, but are not being paid.