- Cancellations continued after the fourth nor'easter to hit the Northeast in three weeks.
- Airlines canceled more than 4,400 flights on Wednesday.
- More than 16,000 flights have been canceled this month so far.
Airlines canceled more than 600 flights scheduled for Thursday, as the fourth major storm in three weeks continued to disrupt air travel in the Northeast.
Carriers said operations were much improved from Wednesday, when they called off more than 4,400 flights.
Travel out of New York's LaGuardia Airport was the most affected on Thursday, with 119 canceled flights, or about a fifth of the day's scheduled departures, according to flight-tracking site FlightAware.
American Airlines, the world's largest airline, said it canceled 230 flights throughout the Northeast, or about 4 percent of its global schedule. American and competitors Delta and United waived date-change fees and fare differences if travelers can fly by March 26. Travelers can also ask for a refund if they can't travel.
Back-to-back snowstorms snarled air travel throughout March. Airlines have canceled more than 16,000 flights to, from or within the U.S., making it the worst March for flight cancellations in at least six years, according to Flight Aware.
Airlines routinely cancel flights and encourage customers to rebook their tickets ahead of time to avoid stranding passengers and to prevent a costly cascade of additional disruptions if planes and crews are out of position.
Travel disruptions can continue even after a storm has passed. In January, several long-haul international flights took off for New York's John F. Kennedy International Airport only to be diverted to other airports when a powerful winter storm halted arrivals. Flights poured in following the storm, leading to a bottleneck and scramble for gates that left passengers sitting on planes for hours and others stranded.