A small airplane carrying mail crashed into a building early Friday in a fiery explosion, killing the pilot, officials said. No one on the ground was injured.

The plane had just taken off from Billings Logan International Airport when it crashed into a construction materials building at 1:25 a.m., Federal Aviation Administration spokesman Mike Fergus said.

"I just watched the light come out of the sky," witness Mike Krausesaid told The Billings Gazette. "To me it looked like the plane was upside down. And then it just came straight down into the lot."

The plane appeared to hit the ground in the lot of a rental business and skid into the construction materials building, witnesses said.

Duane Demars, who lives nearby, said he heard two loud explosions and four smaller ones.

"It sounded excruciating," he said. "When I got here, flames were at a length of 200 to 300 feet and 20 feet high in the air."

The construction materials building and plane were destroyed by the blaze, and a nearby United Rentals building was damaged by debris, Fergus said.

Alpine Air, which owned the plane, confirmed it was carrying mail bound for Great Falls.

Airport fire chief Michael Glancy said at least 300 gallons of jet fuel spilled in the crash, creating puddles that caught fire.