According to flight tracking service FlightAware, airlines canceled more than 2,400 flights Friday to, from or within the U.S. as a major snowstorm bears down on the East Coast.

Another 2,400 were canceled for Saturday. The bulk of those Friday cancellations were in Charlotte and Raleigh, North Carolina. Saturday’s cancellations center around Philadelphia, Washington and — to a lesser extent — New York.

By Sunday afternoon, however, the airlines hope to be back to full schedule to handle the influx of business travelers heading out for the week, one of the busiest travel periods.

The only good news for fliers facing flight cancellations as a winter storm approaches the East Coast: Saturday is the slowest travel day of the week.

According to flight tracking service FlightAware, there are a little more than 22,000 flights scheduled to, from or within the U.S. That’s about 5,000 fewer flights — and 400,000 fewer passengers — than on Thursday or Friday.

All major airlines have issued waivers for travel over the weekend, allowing passengers to rebook onto earlier or later flights to avoid the storms. The airports included vary by airline but include some cities in Kentucky, Tennessee and West Virginia all the way up the coast to New Hampshire and Massachusetts. American Airlines alone has issued waivers for 42 airports.

All flights into and out of Philadelphia International Airport have been canceled for Saturday, when the blizzard conditions are expected to be in full swing.

Airport spokeswoman Diane Gerace says airlines are being proactive ahead of the expected storm and decided to cancel all flights.

She says airlines hope to resume flights Sunday, but travelers should check with their carriers to get detailed information.

The National Weather Service on Friday issued a blizzard warning for Philadelphia and its northern suburbs.

Snow is expected to start falling after 7 p.m. Friday and won’t slow down until Sunday around 10 a.m. As much as 18 inches could fall around Philadelphia, and two feet is possible for inland places like Gettysburg.

(AP)