WASHINGTON (Reuters) -Airlines canceled more than 1,500 U.S. flights on Monday, the fourth consecutive day cancellations have topped 1,000 as government flight cuts and air traffic staffing absences continue to wreak havoc with aviation.

FlightAware, a flight tracking website, said by 8:30 a.m. ET (1330 GMT), more than 1,550 flights had been canceled and 1,400 delayed Monday after 2,950 flights were canceled and nearly 10,800 delayed Sunday in the single worst day for flight disruptions since the government shutdown began on October 1.

A November winter storm in Chicago also disrupting air travel.

The Federal Aviation Administration late Sunday said it was suspending general aviation traffic at 12 airports with air traffic control staffing issues including Chicago O'Hare and Reagan Washington National. The shutdown, which has reached a record 40 days, has led to shortages of air traffic controllers who, like other federal employees, have not been paid for weeks.

The U.S. Senate voted to advance a bill to end the government shutdown late on Sunday.

The FAA instructed airlines to cut 4% of daily flights starting on Friday at 40 major airports because of air traffic control safety concerns. Reductions in flights are mandated to reach 6% on Tuesday and then hit 10% by November 14. One big question for airlines is when will the FAA lift the government-required flight cuts. Transportation Secretary Sean Duffy has said he first wants to see air traffic control staffing and safety data improve.