WASHINGTON, Nov 4 (Reuters) - U.S. Transportation

Secretary Sean Duffy warned Tuesday that if the federal

government shutdown continues another week it could lead to

"mass chaos" and could force him to close some of the national

airspace to air traffic, a drastic move that could upend

American aviation.

"If you bring us to a week from today, Democrats, you will

see mass chaos, you will see mass flight delays. You'll see mass

cancellations, and you may see us close certain parts of the

airspace, because we just cannot manage it," Duffy said at a

press conference Tuesday.

U.S. aviation has already faced tens of thousands of flight

delays over the last month. The comments represented the Trump

administration's most dire warnings of impending impacts from

rising air traffic controller absences.

As the shutdown entered its 35th day, the Federal Aviation

Administration delayed a new round of flights on Tuesday.

Airlines said this week 3.2 million passengers have been hit by

delays or canceled flights due to a spike in air traffic

controller absences.

FAA Administrator Bryan Bedford told Fox Business' "Varney

& Co" on Tuesday that at the agency's largest 30 airports

"anywhere from 20 to 40% of our controllers aren't coming to

work."

Democrats blame Republicans for not negotiating with them to

reopen the government. The shutdown has exacerbated staffing

shortages, forcing 13,000 air traffic controllers and 50,000

Transportation Security Administration officers to work without

pay.

In 2019, widespread disruptions in air travel pressured

lawmakers into ending a 35-day government shutdown during

President Donald Trump's first term in office.

Duffy reiterated he would shutter the U.S. aviation system

if he thought the shutdown was making it too risky to travel.

On Friday, the FAA said nearly half of the 30 busiest U.S.

airports faced shortages of air traffic controllers in the

single worst day since the shutdown began.

In New York on Friday 80% of air traffic controllers were

absent, the agency said.