FAA ground stop live updates: Air travel expected to recover by end of Sunday, FAA chief says

Some travelers on Sunday could be in for another rough day -- with over 900 flights already canceled.

According to FlightAware, 910 flights have been canceled Sunday, and the number is rising.

American Airlines is extending its travel alert and waiving change fees for travel scheduled through Wednesday, Nov. 18.

"American’s recovery from yesterday’s FAA nationwide ground stop continues to move forward," the company said in a statement. "All planned cancellations for tonight and tomorrow have now been completed, though some individual flights may still be canceled as we continue working to fully restore the operation. Our focus tonight is on setting up the operation for a strong start tomorrow, with our crews and aircraft positioned to get customers on their way."

Delta Airlines is encouraging travelers with flexible plans to move their flights to Monday or further out.

Overall, more than 6,400 flights were canceled on Saturday, according to FlightAware, on top of more than 9,000 flights canceled on Friday.

-ABC News' Clara McMichael

The Professional Aviation Safety Specialists (PASS) union, which represents more than 11,000 FAA employees, issued a statement saying its technicians were not involved in the upgrades that resulted in Friday’s ground stop.

"Historically, contractors have followed a protocol where FAA employees conduct a risk assessment and coordinate the maintenance of the system or equipment. PASS-represented technicians were not involved in the upgrades that led to the ground stop yesterday," the union said in the statement.

The union is also saying its members should have a bigger role in the FAA’s air traffic control modernization efforts, arguing that their skills and expertise will help minimize disruptions and make the process quicker.

"PASS fully supports the administration's efforts to modernize the nation's air traffic control system," the union said. "It must be recognized by the FAA that modernization will move more quickly with fewer disruptions if PASS is fully engaged. The employees represented by the union are on the front lines and they have the skills and expertise to make the Brand New Air Traffic Control System (BNATCS) a reality. These employees should receive training on new equipment and could ensure more robust installation and optimization—if the workforce were properly staffed."

-ABC News' Ayesha Ali

Members of rock bands that were traveling to the Vans Warped Orlando concert helped to ease the stress and tension for passengers during flights Saturday.

Videos circulated online of Simple Plan, Hoobastank and The Used performing their hits using the plane's PA system to amused passengers.

Some of the passengers sang along to their songs.

"It felt like a tube of happy people," Hoobastank vocalist Doug Robb said in an interview with Rocksound Saturday.

-ABC News' Malcolm Caminero

Over 5,200 flights have been canceled on Saturday as airlines continue to work around the clock to get operations back up on Saturday.

FAA Administrator Bryan Bedford said the system will be fully recovered on Sunday. As of 3:30 p.m. ET, 160 flights have been canceled on Sunday.

"Based on everything that we’re hearing from our airline partners, they believe that they’ll be able to have full schedule integrity by the close of business on Sunday," he said.

Nearly 9,200 flights were canceled on Friday.