The packed United Airlines passenger plane that hit a light pole while landing at Newark International Airport last month was flying just 19 feet above the busy Jersey Turnpike, an initial investigation showed.

The May 3 flight was cruising below the safe landing path for about three-quarters of a mile before reaching the runway and striking the light pole, according to the early National Transportation Safety Board report obtained by CNN.

It was so low that it was initially thought that the plane’s landing gear struck a passing tractor-trailer. However, the report showed that the truck was actually hit by debris from the struck light pole, injuring the driver.

A Jeep on the highway was also struck by debris, while the driver of the tractor-trailer was injured.

The plane – a Boeing 767 coming in from Italy with 200 passengers — was landing on Runway 29, which starts just 400 feet from the edge of the highway.

Its captain had turned off autopilot to make the landing, but wound up going overspeed because of wind conditions, the report noted.

He then “pulled the power levers back to compensate,” and “returned to a stable airspeed.”

That’s when a co-pilot warned the plane was now coming in “slow” and “a little low” – before people across the aircraft heard what was described as “a thump,” a “mild jolt,” and “a loud bang.”

The plane landed safely, but it suffered “substantial” damage across the fuselage, including punctures and tearing in a landing gear tire.

Nobody on board the aircraft was hurt, while air traffic controllers seemed unaware that anything out of the ordinary had happened.

Terrifying footage from inside the struck truck captured the driver happily singing to himself as he drove along — before he looked out the passenger side window with concern on his face, and the cab rocked with broken glass as the plane soared overhead.

Airport security footage also captured the horrifying sight of the huge plane coming within inches of the top of the truck.

The investigation remains ongoing.