NEW YORK (CNN) -- A US Airways plane with more than 150 people aboard was down in the Hudson River on Thursday after taking off from LaGuardia Airport, and everyone aboard is off the plane and alive, officials said.

Flight 1549, headed to Charlotte, North Carolina, may have experienced a bird strike -- when a bird or flock of birds is sucked into the jet -- according to FAA spokeswoman Laura Brown.

Passenger Alberto Pinero said that within a couple minutes after takeoff, "you just heard a loud bang and the plane shook a bit."

Passengers could smell smoke, and "the plane just started turning. ... We knew something was going on, 'cause look, we were turning back," he said. Everyone on board exited the Airbus A320, the Federal Aviation Administration said.

"Somehow, the plane stayed afloat and we were all able to get on a raft," Pinero said. "It's just incredible now that everyone's still alive."The pilot radioed to air traffic controllers that he had experienced a bird strike and declared an emergency, a New Jersey State Police source told

Pinero said rescue boats arrived immediately. Live video showed the plane bobbing in the water and moving with the current. City fire and police, plus U.S. Coast Guard units, were responding, and a ferry was dropping life jackets into the water.
The pilot tried to return to the airport when the plane fell into the Hudson, The New York Times reported. The Times said it was below 20 degrees in New York at the time the plane went down.

The plane approached the water at a gradual angle and made a big splash, according to a witness watching from an office building.

"It wasn't going particularly fast. It was a slow contact with the water that it made," said the witness, Ben Vonklemperer.

"It appeared not to have landing gear engaged. This was bigger than a puddle-jumper or sea plane. It was a silver aircraft and it basically just hit the water," Vonklemperer added.

An Airbus A320 has 150 seats -- 12 in first class and 138 in economy, according to the Airbus Web site.

People who believe they may have had relatives on the flight may call US Airways at 1-800-679-8215 within the United States, the airline said.