San Francisco, July 23 (Reporter) Two people on board a plane were killed after their aircraft crashed in a farm field near the site of an air show in the U.S. state of Wisconsin on Monday, authorities said. Sheriff's deputies and firefighters responded to the crash in the eastern Wisconsin town of Nekimi on Monday afternoon, the Winnebago County Sheriff's Office said. The names of the people who were killed were not released pending notification of relatives. The National Transportation Safety Board is investigating the crash. The plane crashed about 2 miles (3 kilometers) south of the site of the EAA AirVenture air show at Oshkosh's Wittman Regional Airport. Monday was the first day of the weeklong event, the Oshkosh Northwestern reported...////...