A jetliner trying to land in heavy snow slid off a runway, crashed through a fence and slid into a busy street, hitting one vehicle and pinning another beneath it. A 6-year-old boy was killed.

At least 10 people were injured, authorities said. Eight people of the injured were on the ground. Two passengers on the plane suffered minor injuries, Aviation Department spokeswoman Wendy Abrams said.

Southwest Airlines Flight 1248 from Baltimore was landing at Midway International Airport with 98 passengers and five crew around 7:15 Thursday night when it slid through the fence.

The airport area had 7 inches of snow, but Abrams said runway conditions at the time were acceptable.

The landing seemed normal at first, passenger Larry Vazzano said.

"There was a bump. I saw snow rush over the wing, then there was a big bump," said Vazzano, 54, of Baltimore. "I braced myself on the seat in front of me."

Mike Abate, 35, of suburban Milwaukee, said he could see from the plane that a man was carrying an injured child and that other people were being taken away in an ambulance.

"We were safe on the plane," Abate said. "The toughest part was to realize that someone was under the belly of the plane."