NEW YORK (AP) – JetBlue, still reeling from a Valentine’s Day snowstorm that forced hundreds of canceled and delayed flights, canceled a quarter of its weekend flights Saturday in an extraordinary effort to get back on some semblance of a normal schedule.

“JetBlue is taking this aggressive, unprecedented action to end rolling delays and cancellations, and to operate a new schedule reliably,” the New York-based carrier said in a statement posted on its Web site.

All Saturday and Sunday flights on JetBlue were canceled in and out of 11 airports: Richmond, Va.; Pittsburgh; Charlotte and Raleigh/Durham, N.C.; Jacksonville, Fla.; Austin and Houston, Texas; Columbus, Ohio; Nashville; Portland, Me.; and Bermuda.

As of 6 p.m., about 170 flights had been called off, out of about 600 scheduled for the weekend.

The decision to dramatically reduce operations followed days of chaos at the airline’s terminals, triggered by a Wednesday snow and ice storm that grounded jets at John F. Kennedy International Airport.

As the weekend began the airline was still having trouble getting flight crews in place. Passengers grew increasingly irate.

“There’s screaming matches and fights going on between the passengers and the workers,” one customer, Amanda MacKenzie, 21, said at JFK on Friday.

Baggage handlers also struggled to deal with the mountain of luggage that had been dropped off by passengers, but returned to the terminals because of the cancelations. Some passengers complained that they couldn’t leave the airport, even after their flights were canceled, because no one could find their bags.

JetBlue’s service hot lines also became overwhelmed by people trying to rebook flights.

JetBlue Airways Corp. spokeswoman Alison Eshelman said the airline hoped to put a stop to the angry confrontations by telling passengers far in advance that their plane wouldn’t be flying.

No flights have been canceled yet on Monday.

“And obviously, the focus is not to cancel them,” Ms. Eshelman said.

Affected customers may receive refunds or rebook their flights, the airline said.

The airline said it initially tried to get its system back to normal by selectively canceling flights Thursday and Friday, but long delays continued as a result of constraints that included a one-runway operation at JFK on Thursday, and flight crews burning through the number of hours they are legally allowed to work before taking a rest.

Part of JetBlue’s strategy in the new round of cancelations has been to ground most of its smaller Embraer 190 jets and transfer crews to its larger Airbus A320s.