More than 6,500 flights have been canceled this weekend - this is what you need to know

With one of the largest blizzards in recent history expected to wreak havoc along the East Coast of the US this weekend, airlines have begun to cancel flights.

According to the airline-tracking service FlightAware, airlines have canceled more than 6,000 flights within, into, or out of the US.

More than 3,000 flights were canceled Friday, with another 3,500 grounded for Saturday.

So far the airports hardest hit by cancellations have been concentrated along the Mid-Atlantic region, with Charlotte and the Washington, DC, area airports bearing the brunt.

As the storm moves north, Philadelphia, New York, and Boston are ramping up cancellations in preparation for the effects of the winter storm Jonas. United Airlines will suspend all flights out of Washington D.C. starting at 4pm on Friday and all operations in the New York metro area all day Saturday. The airline hopes to resume operations on Sunday.

The blizzard has created a backup that has rippled across the US, with Atlanta and Chicago reporting more than 100 flight cancellations on Friday.

As a result, airlines have offered passengers with tickets for travel to certain snow-affected airports the opportunity to change their flight schedules at no charge.

If you are traveling on any of these airlines here is what you need to know:

Delta Air Lines:

Delta has offered to refund tickets for passengers whose flights are significantly delayed or canceled as a result of the winter weather. Even if your flight isn't canceled, passengers traveling into, out of or through the affected cities listed here may make a one-time change to their ticket free of charge.

To qualify, passengers must be ticketed to travel between the dates of January 22-24 with tickets reissued on or before January 27 for travel no later than January 27.

Click here for the latest information from Delta Air Lines and a list of cities included Delta's waiver.

American Airlines:

Passengers traveling on American Airlines or America Eagle scheduled to fly into, out of, or through cities affected by the storm may make a one-time change to their itinerary without the need to pay a ticketing fee. To qualify, passengers must be ticketed to fly between January 22-24 with tickets originally purchased before January 21st.

The passengers may switch to a new flight as long as they book in the same class and do not change the destination or origin from their original booking.

Click here for the latest information from American Airlines and the latest list of affected cities.

United Airlines:

Passengers traveling with United Airlines who are affected by the winter storm may also switch to a different flight without paying a change fee. Travelers who quality must be ticketed between the dates of January 22-25 into, out of , or though the affect cities listed on its website.

For qualifying passengers, the airline will waive the change fee and difference in airfare for new flights departing between now and January 29 as long as the new flights are in the same cabin class and between the same cities in the original ticket.

Click here for the latest information from United Airlines and the latest list of affected cities.

JetBlue:

JetBlue will waive change fees and the difference in airfare for passengers traveling into, out of or through cities affected by the blizzard. To qualify, customers must be scheduled to travel between the dates of January 22-24 with tickets purchased before January 20. Affected passengers may re-book for travel between today and January 29. Customers who have had their flights canceled may alternatively opt for a refund.

Click here for the latest information from JetBlue and the latest list of affected cities.

Virgin America:

Virgin America will waive the change fees and the difference in airfare for passengers scheduled to travel between January 22-24 to or from affect cities. Customers have until January 24 to change their travel plans for new flights scheduled for no later than March 10 that are in the same cabin class and between the same cities as the original ticket. Alternatively, qualifying passengers may cancel their itineraries without incurring a cancellation fee.

Click here for the latest information from Virgin America and the latest list of affected cities.

Southwest Airlines:

Passengers flying on Southwest in cities affected the winter storm may also be eligible for to rebook on different. However, the exact parameters for eligibility vary from city to city. 

Click here for the latest information from Southwest and the list of eligible cities.

According to the National Weather Service, parts of the mid-Atlantic states could get as much as 2 feet of snow this weekend, while the New York metro area could get as much as a foot.

Predicting the path and severity of these types of winter megastorms is an inexact science. Last year, the New York area was expected to be clobbered by a massive blizzard that missed the city, unleashing its fury upon Boston instead.

Check back here for updates on further flight delays and cancellations.