This is coolbert:
CAS = Close Air Support.
Here with CAS biplanes of the Second World War.
1. German Hs-123.
"The Henschel Hs 123 was a single-seat biplane dive bomber and close-support attack aircraft flown by the German Luftwaffe during the Spanish Civil War and the early to midpoint of World War II. It proved to be robust, durable and effective especially in severe conditions. It continued to see front-line service until 1944, only to be withdrawn due to a lack of serviceable air-frames and spare parts (production ended in 1940)".
2. Soviet Po-2.
"The Polikarpov Po-2 . . . served as a general-purpose Soviet biplane . . . The reliable, uncomplicated concept of the Po-2's design made it an ideal training aircraft, as well as doubling as a low-cost ground attack, aerial reconnaissance, psychological warfare and liaison aircraft during war, proving to be one of the most versatile light combat types to be built in the Soviet Union."
Surprisingly so [?] the Po-2 even used by North Korean air combat units during the Korean war. Read the last several paragraphs of the operational history of the Po-2 Even a jet downed [indirectly] by a Po-2!!