A vintage airplane flies through the blue sky.
In this June 6, 2016 file photo, a World War II-era Boeing B-17 Flying Fortress airplane banks in the air as it comes in for a landing in Seattle on the anniversary of D-Day.

DALLAS — Two historic military planes collided and crashed to the ground Saturday during a Dallas air show, federal officials said, sending plumes of black smoke billowing into the sky. It was unclear how many people were on board the aircraft or if anyone on the ground was hurt.

Emergency crews raced to the crash scene at the Dallas Executive Airport, about 10 miles from the city’s downtown.

The Boeing B-17 Flying Fortress and a Bell P-63 Kingcobra collided and crashed around 1:20 p.m., the Federal Aviation Administration said in a statement. The collision occurred during the Commemorative Air Force Wings Over Dallas show.

The B-17, an immense four-engine bomber, was a cornerstone of U.S. air power during World War II. The Kingcobra, a U.S. fighter plane, was used mostly by Soviet forces during the war. Most B-17s were scrapped at the end of World War II and only a handful remain today, largely featured at museums and air shows, according to Boeing.

Several videos posted on Twitter showed the fighter plane appearing to collide with the bomber, causing them to quickly crash to the ground, setting off a large ball of fire and smoke.

The FAA and the National Transportation Safety Board were launching investigations.