With more than 6,200 flight cancellations and another 3,700 delays, Thursday has become the worst day for air travel so far of 2014, leaving travelers stranded from North Carolina to Boston as another major snow storm pounds the East Coast. 

"It's the worst day of 2014," said Mark Duell, vice president of operations at the flight tracker FlightAware. 

Prior to this, Jan. 6 was the worst with just 4,110 cancellations. What makes this storm particularly bad for air travel is its widespread nature that has crippled the usually warm southern states of North Carolina and Georgia. Georgia has extended its state of emergency through Sunday.

Charlotte Douglas International Airport in North Carolina reported 540 flight cancellations as  of noon, while Georgia’s Hartsfield-Jackson Atlanta International had cancelled 454, according to data from FlightAware. 

Philadelphia cancelled 426, while New Jersey's Newark Liberty and Washington's Reagan National rounded out the top five worst airports for cancellations with 361 and 358, respectively.

While New York’s LaGuardia and John F. Kennedy remained open, cancellations and delays mounted as the storm made its way up the coast.  

“Many flights have been cancelled in advance of the snow storm please call your airline before coming to the airport,” the Port Authority of New York and New Jersey said on its official airport Twitter feed.

Delta (DAL) was forced to cancel 739 flights across the region, while Southwest (LUV) and U.S. Airways (LCC) cancelled 596 and 560, respectively.

As for the business travelers commuting from the suburbs into New York City and its surrounding airports, Metro-North was running on a reduced schedule at just 75% of capacity with delays stretching across all of its commuter rails in from Long Island and Connecticut.

New Jersey Transit was cross-honoring bus and rail tickets but warned passengers to expect 30 to 60 minute delays systemwide. Bus service through Essex and Morris counties was suspended.

The high-speed commuter train Amtrak operated on a modified schedule on Thursday, with certain lines operating at reduced frequencies.

Follow Jennifer Booton on Twitter at @Jbooton