wicker-bill
n.β Β«Dan hand-cut and shaped a couple of pieces of sheet metal that looked like angle-ironsβjust 90 degree bent pieces of aluminum. He had us mount them on the back edges of the rear wing of the car.…His simple “wicker-bill” inventionβalso known as the Gurney Flapβhad given us another four miles per hour.Β» βby Bobby Unser Winners Are Driven Feb. 14, 2003. (source: Double-Tongued Dictionary)