Five people, including two boys, were killed yesterday when their small plane crashed at a New Jersey airport, scattering debris more than 200 feet.

The plane had just taken off from Monmouth Executive Airport for a sightseeing tour of New York City when it ran into trouble at about 3:45 p.m. and the pilot tried to return, a police spokesman said.

Dana McNally, 39, who witnessed the crash, told the Asbury Park Press that she saw something — possibly the tail — break off.

The plane, she said, veered right and nose-dived into a snow-covered field alongside the runway.

“It hit face first,” McNally said. “It just went right in nose first.”

Another witness, Barry Kennedy, who was sledding with his 5-year-old son, told the paper he realized something was wrong when he saw the plane near the top of the trees with its landing gear still retracted.

“He banked right and, all of a sudden, all of this stuff came off the left side of the tail,” Kennedy said.

He said the plane climbed about 50 feet before crashing into the ground.

Police would not immediately identify the victims.

The two boys, described only as adolescents, were related to one of the adults. The other two adults were the plane’s owner and a pilot, authorities said.

“The two [boys]” were thrown from the plane, Police Capt. Tim Clayton told The Post. “One adult was found inside the plane, while the other was found either underneath the plane or inside as well.

“We used thermal imaging to locate the fifth victim,” he said.

Relatives of the victims were at the airport, but it was not clear whether they had witnessed the crash.

The plane was a twin-engine Cessna 337 Skymaster. The model is known as “push me, pull you” because its twin engines are located in the nose and behind the fuselage. With Post Wire Services