A flyover before Iowa’s Nov. 20 football game against Ohio State University may have been in violation of Air Force rules, according to the Associated Press.

Maj. Chris Kopacek said the Air Force pilots had permission to fly at 500 feet, but 1st Lt. Kate Roling, a spokeswoman for Vance Air Force base, said the four planes should have flown at least 1,000 feet above the ground. An investigation is underway, the AP said.

— by Nora Heaton