United Airlines said customers in storm-affected cities will be allowed to reschedule their itineraries "with a one-time date or time change, and the airline will waive the change fees."
Delta, Jet Blue, Southwest and other airlines offered their customers similar assurances.
In Connecticut, Gov. Dannel Malloy said utility companies were bringing additional crews from out of state to deal with potential power outages. Metro-North rail lines could also be closed at any time should winds exceed 40 mph.
The Connecticut National Guard has moved equipment to staging places, including several Black Hawk helicopters at Bradley International Airport north of Hartford. In Rhode Island, 300 members of a military police brigade were scheduled to drill on Saturday and Sunday but the drill has been moved up because of the storm.
A snow emergency went into effect in the southern Connecticut city of Stamford, beginning at 5 p.m.
In New York, Mayor Michael Bloomberg said the timing of the storm could actually benefit municipal workers.
"If it's going to happen, having it happen Friday overnight into Saturday is probably as good timing as we could have," Bloomberg said. "The sanitation department then has the advantage of being able to clean the streets when there's normally less traffic."
New York's Air National Guard unit on Long Island has some snowmobiles it can deploy to help with search and rescue or emergency transportation. If Gov. Andrew Cuomo were to order the National Guard to assist, each of New York's Guard's six operating areas will be ready to deploy 10 Humvees and 40 troops trained in disaster response.
By late Thursday, the National Weather Service had issued a blizzard warning from 6 a.m. Friday until 1 p.m. Saturday, with wind gusts up to 50 mph, creating dangerous driving conditions with visibilities near zero in white-out conditions.
Consolidated Edison, a main utility company for the New York region, said it is preparing additional crews to deal with potential power outages and advised customers to stay clear of downed power lines.
Long island Power Authority, which received intense criticism over its handling of Superstorm Sandy, said it was preparing.
Record-breaking snowfall could hit Hartford, Connecticut, as well.
"We expect snow and then rain, and severe coastal flooding," said CNN meteorologist Sarah Dillingham.
Wind will also be a major concern. Gusts could reach 75 mph along Cape Cod and 55 mph in the Long Island Sound and cause coastal flooding, with tides rising about three to five feet.
As more miserable weather slams the region, those affected by Superstorm Sandy will be further hampered by high winds, cold temperatures and more beach erosion.
Parts of the region are under a blizzard watch.
In New Hampshire, there are people who actually want a lot of snow.
"Natural snow definitely gets people to remind them that there are winter activities," Lori Rowell, director of marketing for Pats Peak ski resort in Henniker, told CNN affiliate WBZ.
Steve Livingston said he usually sells 30 to 35 snowmobiles a week at his shop, but he hasn't sold any in the past week.
Sales have been super slow," said Livingston, owner of Livingston's Arctic Cat in Hillsborough. "I hope we get as much snow as we can possibly deal with. That would be like a hot summer day for Hampton Beach for us."