As Sandy moved west as a post-tropical cyclone, East Coast air travel began to gear back up on Tuesday.
Airports in Boston, Philadelphia and Washington reopened. Two major New York airports, Kennedy and Newark, reopened at 7 a.m. Wednesday, but both airports said that there would be limited service. LaGuardia remains closed.
Sandy continued to have an impact on air traffic even after leaving the New York area. On Tuesday night, American Airlines reported that high winds from Sandy were causing delays at Chicago O'Hare. The Chicago Tribune had dramatic video footage of high winds driving waves onto the city's North Avenue and Oak Street beaches.
Back in New York, an indicator of how far water surged on LaGuardia's runways could be seen in photos JetBlue Airways tweeted and posted on its blog
Boston and Philadelphia airports are operating with a limited number of flights. Delta and some foreign carriers are operatimg a limited number of flights into Washington Dulles.
Delta is also flying a limited number of flights into Baltimore-Washington and Washington Reagan airports.
Flight Aware, the flight-tracking site, said the number of flights canceled because of Sandy increased to more than 19,500. It said that 2,801 flights had been canceled for Wednesday, and 481 have been canceled for Thursday.
Flight Aware expected the number of cancellations to increase, depending on how quickly Kennedy and Newark ramp up service.
Mass transit disruptions in New York are hindering airlines' ability to resume service, according to Flight Aware's update.
Airlines, which had already said they would waive penalties for travelers flying through airports affected by Sandy, extended those deadlines for those going through New York-area airports.
JetBlue extended its waiver to Nov. 14. Its COO, Rob Maruster, tweeted that the airline would operate only arrivals into Kennedy on Wednesday, would be up to 50% service Thursday, 75% on Friday and 100% on Saturday.
Delta extended its penalty waiver for changing tickets to Nov. 9 for passengers originally scheduled to travel through New York airports Oct. 30 to Nov. 3. It changed the deadline for travelers flying through airports in Washington, Pennsylvania and several Northeastern states to Nov. 9.
American Airlines applied its penalty waiver for passengers scheduled to travel thorugh New York airports Oct. 30 through Nov. 7. United Airlines is waiving change fees for travelers scheduled to travel through New York airports Oct. 30 through Nov. 2.
The Federal Aviation Administration issued a statement saying that it "is continuing to work with airlines, airports and other operators, as well as federal and state partners to restore the country's aviation system in the areas affected by Hurricane Sandy."
The agency said that its goal is to "quickly re-establish its air traffic service and other capabilities that enable aviation operations to support disaster-relief efforts."
The FAA is assessing damage and providing assistance to affected airports. Follow Kate Rice on Twitter @krtravelweekly.