A B-17 bomber crashed at Bradley International Airport in Connecticut on Wednesday morning, killing at least seven people and injuring six others, authorities said. The World War II-era plane crashed on the runway, bursting into flames and sending up a huge plume of black smoke that could be seen for miles. The aircraft, operated by the Collings Foundation, was one of five vintage WWII fighter planes on display at the airport on a stop for the Wings of Freedom tour, a traveling exhibit that honors WWII veterans who served during the war. According to witnesses, the plane, known as the “flying fortress,” was flying low before it crash-landed. “He was treetop level when I saw him... and one of the engines wasn't spinning,” Laura Nolan, who was driving nearby at the time of the incident, told the Hartford Courant. Kevin Dillon, executive director of the Connecticut Airport Authority, said the aircraft had appeared to encounter problems with gaining altitude and had “lost control” while attempting to return to the runway, The Boston Globe reports.