More than 1,000 total flights have been canceled across the U.S. on Friday. Another 4,300 have been delayed, according to data from FlightAware.

President Trump called on Senate lawmakers to stay in session until the government shutdown ends. It's currently the longest shutdown in U.S. history.

“The United States Senate should not leave town until they have a Deal to end the Democrat Shutdown. If they can’t reach a Deal, the Republicans should terminate the Filibuster, IMMEDIATELY, and take care of our Great American Workers!” Trump wrote in a social media post on Friday.

Earlier on Friday, Senate Minority Leader Chuck Schumer laid out an offer saying Democrats would agree to end the shutdown in exchange for a one-year extension of enhanced Affordable Care Act subsidies and a stopgap bill, along with three full-year funding bills.

“Democrats have said we must address the health care crisis, but Republicans have repeatedly said they won’t negotiate to lower the health care costs until the government reopens,” Schumer said on the Senate floor. “So let’s find a path to honor both positions."

Senate Majority Leader John Thune was quick to reject the Democrats' proposal, saying the offer was a "nonstarter."

“I guess you could characterize that as progress,” Thune told reporters. "But I just don’t think it gets anywhere close to what we need to do here."

Officials at Denver International Airport announced earlier this week that they had submitted a request to the Federal Aviation Administration to be granted the ability to pay air traffic controllers out of the airport's own revenue. Under the airport's proposal, the federal government would reimburse the funds after the shutdown is over.

"This is a critical time for travel both here at DEN and around the country. Staffing issues are already being identified at a number of airports, impacting travel. As the shutdown drags on, air traffic controllers, in particular, are being stressed unnecessarily," Denver airport CEO Phil Washington wrote in a statement.

Neither the airport nor the FAA has provided an update on the status of the request.

Reagan National Airport in the Washington, D.C., area is expecting "significant delays and cancellations" due to the FAA's flight cuts. According to FlightAware, the airport (DCA) is currently experiencing the most delays for inbound and outbound flights.

"Airlines will reach out directly to affected customers regarding flight cancellations or rescheduling options," according to the airport's website.

While there have been hundreds of flight cancellations today, things could have been much worse.

According to data from Cirium cited by the New York Times, 25,375 flights were scheduled to fly on Friday in the United States.

Per FlightAware, more than 900 were canceled as of 3 p.m. ET, or about 3.5% — which roughly matches or is even slightly below the initial 4% reduction in flights imposed by the FAA today.

Delays are another story. More than 3,500 flights have been delayed, or nearly 14% of those scheduled.

United and American Airlines have announced hundreds of flight cancellations through the weekend in an effort to comply with the FAA's flight reductions.

The following are the number of flights United has canceled among the roughly 4,500 it had scheduled for each day:

• Friday: 184

• Saturday: 168

• Sunday: 158

American Airlines said it will cancel approximately 220 of its 6,000 flights scheduled through Monday.

Speaking at an event hosted by Breitbart News in Washington, D.C., Transportation Secretary Sean Duffy said that the percentage of flight reductions could double in the coming weeks if the shutdown continues.

“If this continues, and I have more controllers who decide they can’t come to work, can’t control the airspace, but instead have to take a second job — with that, you might see 10 percent would have been a good number, because we might go to 15% or 20%,” Duffy said when asked what holiday travelers should expect.

According to FlightAware, there have been at least 850 cancellations and nearly 3,000 delays for flights within, into or out of the United States as of 2 p.m. ET.

Here are the airports with the most delayed flights (by origin airport):

• Chicago O'Hare (ORD): 40

• Hartsfield-Jackson International (ATL): 38

• Denver International (DEN): 35

• Dallas-Fort Worth (DFW): 32

• Los Angeles International (LAX): 28

• Phoenix Sky Harbor International (PHX): 27

• San Francisco International (SFO): 24

• Newark Liberty International (EWR): 23

• Las Vegas Harry Reid International (LAS): 21

• Charlotte/Douglas International (CLT): 21

And here are the airports with the most cancellations (also by origin):

• Chicago O'Hare (ORD): 120

• Hartsfield-Jackson International (ATL): 119

• Ronald Reagan Washington National (DCA): 100

• Newark Liberty International (EWR): 92

• George Bush Houston Intercontinental (IAH): 79

• Miami International (MIA): 72

• Denver International (DEN): 70

• Orlando International (MCO): 61

• New York John F. Kennedy International (JFK): 60

• Houston Hobby (HOU): 58

Transportation Secretary Sean Duffy said Friday that if the government were to reopen today, the flight reductions imposed by the FAA would not be lifted immediately because all air traffic controllers who have been calling out probably won't return to work right away.

"It’s going to take time to get them all back in,” Duffy told reporters at Reagan National Airport in Arlington, Va., relaying the message he said he's received from the National Air Traffic Controllers Association, which represents 15,000 of the country’s air traffic controllers.

“As we see the data change and more controllers come to work, we are as quickly as possible going to take these restrictions away,” Duffy said. “That’s the best approach.”

To comply with the FAA's mandate to reduce flights, Delta Air Lines said it had completed all planned flight reductions for Friday, Saturday and Sunday.

Delta customers affected by the cancellations have been notified and automatically rebooked on the next best available flight. For those who prefer not to travel, refunds are available.

FlightAware currently shows over 850 total flight cancellations across major airlines within, into or out of the U.S. today. For Saturday, there are 695 total flights canceled, and on Sunday, there are 328 canceled. For reference, there were 171 flights canceled on Wednesday, the day before the FAA announced that it was reducing flights.

These are the 10 airlines with the most cancellations as of 1 p.m. ET on Friday, according to Flightaware:

• Skywest: 176

• Southwest: 129

• Republic: 83

• Endeavor: 79

• United: 67

• Evoy: 61

• PSA: 41

• Delta: 32

• Piedmont: 30

• JetBlue: 25

Yes, airlines will be required to issue full refunds if your flight is delayed or canceled, the FAA says. However, the airline won't be required to cover secondary costs, like food or a hotel, while waiting for a rescheduled flight. This is the standard policy if the cancellation or delay is not the airline's fault.

To check to see what your airline covers in the event your flight is canceled or delayed, you can check the Department of Transportation website here.

Airlines for America, a trade association that advocates for leading U.S. airlines, urged Congress to reopen the federal government in order to "get federal workers paid and get our airspace back to normal operations" ahead of the upcoming holiday travel season.

In a series of posts on X on Friday, the association drew attention to the unprecedented length of the government shutdown, as air traffic controllers and TSA officers aren't receiving pay.

"More than 3.5 million passengers have experienced delays or cancelations because of air traffic control staffing concerns since the shutdown began," reads one of the posts. "This simply is not sustainable."

Airlines for America also pointed to the upcoming busy Thanksgiving travel season, writing, "We are expecting 31 million passengers — an all-time high — over the holiday (November 21-December 1)."

The FAA stated that a reduction in flight operations nationwide will be gradual. Here's the schedule:

• Friday, Nov. 7: 4% reduction in flights

• Tuesday, Nov. 11: 6% flight reduction

• Thursday, Nov. 13: 8% reduction

• Friday, Nov. 14: full 10% reduction in flights will take effect

"These actions were directly informed by the FAA’s review of aviation safety data, including voluntary, confidential safety reports that pilots and air traffic controllers file," according to the U.S. Department of Transportation. "The data indicates increased stress on the system, which increases risk."

This is the full list of 40 airports being affected nationwide by the FAA's 10% flight reduction:

• Anchorage International (ANC)

• Baltimore/Washington International (BWI)

• Boston-Logan International (BOS)

• Charlotte Douglas International (CLT)

• Chicago Midway International (MDW)

• Chicago O'Hare International (ORD)

• Cincinnati/Northern Kentucky International (CVG)

• Dallas-Fort Worth International (DFW)

• Dallas Love Field (DAL)

• Denver International (DEN)

• Detroit Metropolitan Wayne County (DTW)

• Fort Lauderdale-Hollywood International (FLL)

• George Bush Houston Intercontinental (IAH)

• Hartsfield-Jackson Atlanta International (ATL)

• Honolulu International (HNL)

• Houston Hobby (HOU)

• Indianapolis International (IND)

• Las Vegas Harry Reid International (LAS)

• Los Angeles International (LAX)

• Louisville Muhammad Ali International (SDF)

• Memphis International (MEM)

• Miami International (MIA)

• Minneapolis-Saint Paul International (MSP)

• New York LaGuardia (LGA)

• New York John F. Kennedy International (JFK)

• Newark Liberty International (EWR)

• Oakland San Francisco Bay International (OAK)

• Ontario International (ONT)

• Orlando International (MCO)

• Philadelphia International (PHL)

• Phoenix Sky Harbor International (PHX)

• Portland International (PDX)

• Ronald Reagan Washington National (DCA)

• San Diego International (SAN)

• Salt Lake City International (SLC)

• San Francisco International (SFO)

• Seattle-Tacoma International (SEA)

• Tampa International (TPA)

• Teterboro (TEB)

• Washington Dulles International (IAD)