At least four people have been killed and five critically injured after a small plane crashed into an airport building in Kansas in the United States.<br /><br />It happened at the Mid-Continent Airport in the city of Wichita on Thursday morning.<br /><br />The aircraft lost an engine on take off and slammed into the flight safety building taking down the roof on one side, and causing what was described as a “horrific fire.”<br /><br />There were about 100 people inside the building at the time and four people are still unaccounted for.<br /><br />Flights to and from the airport are still operating normally.