WASHINGTON, Oct 31 (Reuters) - Nearly 50% of the 30

busiest U.S. airports are grappling with shortages of air

traffic controllers, the Federal Aviation Administration said on

Friday, leading to flight delays nationwide as a federal

government shutdown hit its 31st day.

The absence of controllers is by far the most widespread

since the shutdown began, with one of the worst-hit regions

being New York, where 80% of air traffic controllers were out,

the regulator said.

It delayed flights at airports in Austin, Newark and

Nashville as air traffic control staffing problems snarl

flights.

At least nine FAA facilities reported staffing problems

earlier in the day, with the regulator saying it was likely to

delay flights later at airports in the Houston and Dallas area.

Flight delays were averaging 61 minutes at Nashville, 50

minutes at Austin and 101 minutes at Newark.

By 12:30 a.m. ET, Aviation tracking site FlightAware showed,

2,200 U.S. flights had been delayed and 300 canceled.

U.S. Transportation Secretary Sean Duffy said he expected

more flight delays in the next few days.

"Coming into this weekend and then the week after, I think

you are going to see even more disruptions in the airspace,"

Duffy said on Fox News' "America's Newsroom."

On Thursday, air traffic control staffing shortages snarled

flights at Orlando, Dallas/Fort Worth and Washington, D.C., when

FlightAware data showed 7,300 flights delayed and 1,250

canceled across the United States.

The shutdown has forced 13,000 air traffic controllers and

50,000 Transportation Security Administration officers to work

without pay.

Delta Air Lines ( DAL ), United, Southwest Airlines ( LUV ) and American

Airlines ( AAL ) have all called on Congress to quickly pass a stop-gap

funding bill to let the government reopen amid talks on disputes

over healthcare policy.

The shutdown has led to flight delays due to air traffic

controller absences and affected thousands of flights, the

Transportation Department said.

The shutdown began on October 1 and continued since as a

federal funding bill has stalled in Congress.

Republican lawmakers want to pass a "clean" funding measure

with no strings attached, while Democrats have demanded talks on

extending health-care subsidies set to expire at year-end.

Airlines have repeatedly urged an end to the shutdown,

citing aviation safety risks.

The shutdown has exacerbated existing staffing shortages,

threatening to cause widespread disruptions similar to those

that helped end a 35-day government shutdown in 2019.

The FAA is about 3,500 air traffic controllers short of

targeted staffing levels and many had been working mandatory

overtime and six-day weeks even before the shutdown.