Spoilers Inc. - In aeronautics, a spoiler (sometimes called a lift spoiler or lift dumper) is a device intended to reduce lift in an aircraft. Spoilers are plates on the top surface
What is the Purpose of Spoilers on a Plane? - Aeroclass.org
Airplane Parts and Function | Glenn Research Center | NASA
Spoiler animations - Features - Infinite Flight Community
Why does spoiler extension cause straight-wing Learjets to pitch down, rather than up, and why did it take so long to discover this? - Aviation Stack Exchange