An airport and two airplanes on the ground were evacuated for several hours after nine bomb threats were phoned in, authorities said. The evacuation at Bishop International Airport in Flint, about 60 miles (100 kilometers) northwest of Detroit, began shortly after the threats were called in to the airport's rescue department around 5 p.m. Wednesday, said Tad Hutcheson, vice president of marketing for AirTran Airways, the airport's biggest carrier. Norm Brewer, a Transportation Security Administration spokesman in Washington, said shortly before 9 p.m. that operations at the airport had returned to normal. Brewer said he did not know if any bombs were found or whether there were any suspects or arrests. Airport spokeswoman Pat Corfman said four or five flights had to be diverted while bomb-sniffing dogs searched the terminal. It was not immediately clear where the flights were diverted. FBI agents were assisting local authorities, said Dawn Clenney, a spokeswoman for the bureau's Detroit office, declining to give details about the threats. More than 1 million passengers traveled through the airport last year, according to its Web site.