The Curtiss A-12 Shrike was the United States Army Air Corps' second monoplane ground-attack aircraft, and its main attack aircraft through most of the 1930s. It was based on the A-8, but had a radial engine instead of the A-8's inline, water-cooled engine, as well as other changes.
Curtiss A-12 Shrike
Formation of Curtiss A-12 Shrikes during exercises near Wheeler Field, Oahu, Hawaii circa 1940.
An A-12 awaiting delivery to the ROCAF
An attack aircraft, strike aircraft, or attack bomber is a tactical military aircraft that has a primary role of carrying out airstrikes with greater precision than bombers, and is prepared to encounter strong low-level air defenses while pressing the attack. This class of aircraft is designed mostly for close air support and naval air-to-surface missions, overlapping the tactical bomber mission. Designs dedicated to non-naval roles are often known as ground-attack aircraft.
A USAF A-10 Thunderbolt II attack aircraft in flight
An A-1 Skyraider of the USAF
RAF Harrier GR9 in flight, 2008
Boeing GA-1, ~1920