Air travel restrictions imposed at many of the nation’s largest airports because of the government shutdown are expected to continue, even as the end appears near, Transportation Secretary Sean Duffy said Tuesday.

The Federal Aviation Administration reduced flights throughout the U.S. by 6% on Tuesday, a day after the Senate approved a bipartisan spending package to end the shutdown. The legislation still needs to clear the House before President Donald Trump can sign it and officially end the shutdown.

On Friday, the FAA began reducing flight capacity at 40 "high traffic" airports, with a 4% decrease. That reduction is expected to rise from 6% on Tuesday to 8%, and then 10% later in the week. More than 9,000 flights reportedly have been canceled since the restrictions began.

"Some have asked when will you start rolling those back?" Duffy said at a news conference at the Central Wisconsin Airport in Mosinee. "The answer to that is this has all been data-based. We have seen incursions on runways. We have seen loss of separation in the airspace, and we have seen heightened complaints by pilots of the communication they are having with air traffic controllers. When this information goes in the wrong direction, we have to make decisions to keep people safe.

"You all saw with the DCA air crash. The last administration did not see the 85 near misses that happened in that airspace. They did not take action. They did not look at the data. We will make the best decisions possible to keep the traveling public safety at that is what we have done. When that data changes, we will start taking down from 6, maybe we will go from 4, 2 and get back to normal air traffic."

Duffy stressed that having a systemwide reduction is far safer than seeing hot spots across the country and random cancellations and delays that leave airplanes stuck at certain airports.

"We think that this is the best approach to reduce the risk in the system and improve safety," he said.

Duffy said he was encouraged that more air traffic controllers have been reporting for work. He said there were only four staffing triggers Tuesday — the FAA uses "staffing trigger" to indicate when controller levels at a facility fall below planned minimums — compared with 81 on Saturday. Air traffic controllers are among thousands of federal workers who have been going without pay during the shutdown. Many are either not reporting for work or have taken second jobs to make ends meet.

"I encourage every single Republican and Democrat to vote to open the government," Duffy said. "I do not want to be chicken little for you all. If the government does not open, the House does not do its job. … I've had questions about what happens for Thanksgiving. What will happen during that timeframe? We will not get to Thanksgiving.

"You will see this Friday, Saturday and Sunday, big disruption thus far, massively more disruption as we come into the weekend if the government does not open. It is going to radically slow down. The House has to do its work. By the way, I am very hopeful. It seems like they are in a good mood to come in and open the government. Again, I hope that they do that."