NEW YORK — Flights resumed, but slowly. The New York Stock Exchange got back to business, but on generator power. And with the subways still down, great numbers of people walked across the Brooklyn Bridge into Manhattan in a reverse of the exodus of 9/11.

Two days after Superstorm Sandy rampaged across the Northeast, killing at least 62 people, New York struggled Wednesday to find its way. Swaths of the city were still without power, and all of it was torn from its daily rhythms.

At luxury hotels and drugstores and Starbucks shops that bubbled back to life, people clustered around outlets and electrical strips, desperate to recharge their phones. In the Meatpacking District of Manhattan, a line of people filled pails with water from a fire hydrant. Two children used jack-o’-lantern trick-or-treat buckets.

Gov. Andrew Cuomo said that parts of the subway would begin running again Thursday, and that three of seven tunnels under the East River had been pumped free of water, removing a major obstacle to restoring full service.

“We are going to need some patience and some tolerance,” he said.

On Wednesday, both were frayed. Bus service was free but delayed, and New Yorkers jammed on, crowding buses so heavily that they skipped stops and rolled past hordes of waiting passengers.

New York City buses serve 2.3 million people on an average day, and two days after the storm they were trying to handle many of the 5.5 million daily subway riders, too.

As far west as Wisconsin and south to the Carolinas, more than 6 million homes and businesses were still without power, about 4 million of them in New York and New Jersey.

Mayor Michael Bloomberg said 500 patients were being evacuated from Bellevue Hospital because of storm damage. The hospital has run on generators since the storm. About 300 patients were evacuated from another Manhattan hospital Monday after it lost generator power.

Still, there were signs that New York was flickering back to life and wasn’t as isolated as it was a day earlier.

Flights resumed at Kennedy and Newark airports on what authorities described as a very limited schedule. Nothing was taking off or landing at LaGuardia, which suffered far worse damage.

The stock exchange, operating on backup generators, came back to life after its first two-day weather shutdown since the blizzard of 1888. Mayor Michael Bloomberg rang the opening bell to whoops from traders below.

“We jokingly said this morning we may be the only building south of midtown that has water, lights and food,” said Duncan Niederauer, CEO of the company that runs the exchange, in hard-hit lower Manhattan.

Most Broadway shows returned for Wednesday matinees and evening shows.

Across the Hudson River in New Jersey, National Guardsmen in trucks delivered ready-to-eat meals and other supplies to heavily flooded Hoboken and rushed to evacuate people from the city’s high-rises and brownstones. The mayor’s office put out a plea for people to bring boats to City Hall for use in rescuing victims.

Natural gas fires erupted in Brick Township, where scores of homes were wrecked by the storm. And some of the state’s barrier islands, which took a direct hit from Sandy on Monday night, remained all but cut off.

President Barack Obama took a helicopter tour of the ravaged coast with New Jersey Gov. Chris Christie.

“The entire country has been watching what’s been happening. Everybody knows how hard Jersey has been hit,” Obama said at a shelter in Brigantine, N.J. He promised people there that the federal government was “here for the long haul.”

In New York, masses of people walked shoulder-to-shoulder across the Brooklyn Bridge to get into Manhattan for work, reminiscent of the escape scenes from the Sept. 11 terrorist attack and the blackout of 2003.

They entered an island sharply divided between those who had power and those who did not.

In Manhattan at night, it was possible to walk downtown along an avenue and move in an instant from a mostly normal New York scene — delis open, people milling outside bars — into a pitch-black cityscape, with police flares marking intersections.

People who did have power took to social media to offer help to neighbors.

“I have power and hot water. If anyone needs a shower or to charge some gadgets or just wants to bask in the beauty of artificial light, hit me up,” Rob Hart of Staten Island posted on Facebook.

A respected New York steakhouse in the blackout zone, Old Homestead, realized its meat was going to go bad and decided to grill what was left and sell steaks on the sidewalk for $10. A center-cut sirloin usually goes for $47.

Simon Massey and his 9-year-old son, Henry, took one last walk near their powerless apartment in downtown Manhattan before decamping to a friend’s place in Brooklyn where the electricity worked.

“We’re jumping ship,” he said. “We gorged on eggs and sausage this morning before everything goes bad. We don’t want to spend another three or four days here.”

They live on the 10th floor of a 32-floor building, where they were flushing the toilet with water from their filled tub and cooking on their gas stove. They found their way down the stairs with glowsticks and flashlights, and rationed iPad and phone use.

“I’m feeling scared,” said Henry, who was home from third grade for a third straight day. “It just feels really, really weird. New York’s not supposed to be this quiet.”