(Reuters) – Two planes collided midair on Saturday at a World War Two commemorative airshow in Dallas, federal officials said. A Boeing B-17 Flying Fortress bomber and a Bell P-63 Kingcobra fighter collided and crashed at the Wings Over Dallas Airshow at Dallas Executive Airport at 1:20 p.m. CST (1820 GMT), the Federal Aviation Administration (FAA) said in a statement. Emergency crews were responding to the crash, airport officials said on Twitter. The show is described as the nation’s premiere World War Two airshow. It was unclear how many people were aboard the two aircraft, the FAA said. Vi…