The Federal Aviation Administration said Saturday that half of the 30 major U.S. airports are experiencing air traffic controller shortages due to the government shutdown. The Federal Aviation Administration posted on social media

U.S. Transportation Secretary Sean Duffy warned on Thursday that if the government shutdown continues, air traffic could be in catastrophic situations as November coincides with peak travel season. At present, because air traffic control personnel are not paid, they may refuse to go to work, which will cause large-scale flight delays.

The new fiscal year in the United States began on October 1, but Congress failed to approve the budget in time, resulting in the government being unable to operate normally. The shutdown means some government agencies supported by direct appropriations from Congress will cease operations because a budget for the next fiscal year has not yet been passed.

Trump has previously emphasized that he may use the government shutdown to make large-scale layoffs and payment adjustments. He said the difficulty in agreeing on a budget was due to Democratic positions and that the White House took the opportunity to eliminate projects that Republicans did not approve of.