Chiropractors in the Council Bluffs area may find their offices busier next week from so many people spending the weekend craning their necks skyward. The U-S Navy’s Blue Angels flying team will buzz southwestern Iowa as part of an air show at Nebraska’s Offutt Air Force Base near Omaha. There are also parachute teams and aerobatic teams.An Offutt spokesman says there is -no- admission charge for the air show, dubbed “Defenders of Freedom,” but people who attend need to use common sense. He says there will be security at the show since it is at an airport.Gates open for the air show both Saturday and Sunday at 9 A-M. The Blue Angels fly at more than 300 miles an hour in their F-A-18s. For those preferring a slower venture, free flight simulators will be set up too.