Question: Don R. Berlin designed what American ground-attack aircraft that first flew in 1938?

Context paragraphs:
Don R. Berlin: Donovan Reese Berlin (June 13, 1898 – May 17, 1982) was an American military aircraft designer and aircraft industry executive.  Among the many designs with which he is associated, are the Curtiss P-36 Hawk, Curtiss P-40 Warhawk and Fisher P-75 Eagle.  His name is "synonymous with the development of military aviation".  He designed aircraft that were safe, rugged and "a pilot's joy."

Soko G-2 Galeb: The Soko G-2 Galeb (English: Seagull ) is a Yugoslav single engine, two-seater jet trainer and light ground-attack aircraft.  The G-2 was developed during the 1950s by the Aeronautical Technical Institute at Žarkovo as a replacement for the Lockheed T-33 in service with the Yugoslav Air Force ( – RV i PVO).  Production started in 1965 at the Soko aircraft factory in Mostar, and ended in 1985 with 248 aircraft delivered.  The G-2 had the distinction of being the first mass-produced jet aircraft in socialist Yugoslavia.  It also served as a basis for the single-seat ground-attack J-21 Jastreb.

IAR 80: The IAR 80 was a Romanian World War II low-wing monoplane, all-metal monocoque fighter and ground-attack aircraft.  When it first flew, in 1939, it was comparable to contemporary designs being deployed by the airforces of the most advanced military powers.  Production problems and lack of available armament delayed entry of the IAR 80 into service until 1941.  It remained in frontline use until May 1945.

V bomber: The term V bomber was used for the Royal Air Force (RAF) aircraft during the 1950s and 1960s that composed the United Kingdom's strategic nuclear strike force known officially as the V-force or Bomber Command Main Force.  The strategic bombers, whose names all started with the letter "V" and which were known collectively as the "V-class", included the Vickers Valiant (first flew 1951, entered service 1955), Avro Vulcan (first flew 1952, in service 1956) and Handley Page Victor (first flew 1952, in service 1958).  The V-Bomber force reached its peak in June 1964, with 50 Valiants, 70 Vulcans and 39 Victors in service.

Curtiss P-40 Warhawk: The Curtiss P-40 Warhawk is an American single-engined, single-seat, all-metal fighter and ground-attack aircraft that first flew in 1938.  The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time and enabled a rapid entry into production and operational service.  The Warhawk was used by most Allied powers during World War II, and remained in frontline service until the end of the war.  It was the third most-produced American fighter, after the P-51 and P-47; by November 1944, when production of the P-40 ceased, 13,738 had been built, all at Curtiss-Wright Corporation's main production facilities at Buffalo, New York.

Sopwith Salamander: The Sopwith TF.2 Salamander was a British ground-attack aircraft of the First World War designed by the Sopwith Aviation Company which first flew in April 1918.  It was a single-engined, single-seat biplane based on the Sopwith Snipe fighter but with an armoured forward fuselage to protect the pilot and fuel system from ground fire during low level operations.

Tareq Ayyoub: Tareq Ayyoub (Arabic: طارق أيوب‎ ‎ , also spelled "Tarek Ayoub", "Tarik Ayub", 1968 - 8 April 2003) was an Arab television reporter of Palestinian nationality, employed by Al Jazeera, and previously by Fox News.  Ayyoub was killed in 2003 when two missiles, fired from by an American ground-attack aircraft, struck the Baghdad headquarters of the Al Jazeera Satellite Channel during the 2003 Invasion of Iraq.  The Al Jazeera station was clearly marked as a media centre, and the US military had been informed of its location in February.

Junkers Ju 87: The Junkers Ju 87 or Stuka (from "Sturzkampfflugzeug", "dive bomber") was a German dive bomber and ground-attack aircraft.  Designed by Hermann Pohlmann, it first flew in 1935.  The Ju 87 made its combat debut in 1937 with the Luftwaffe's Condor Legion during the Spanish Civil War and served the Axis forces in World War II.

Junkers CL.I: The Junkers CL.I was a ground-attack aircraft developed in Germany during World War I.  Its construction was undertaken by Junkers under the designation J 8 as proof of Hugo Junkers' belief in the monoplane, after his firm had been required by the "Idflieg" to submit a biplane (the J 4) as its entry in a competition to select a ground-attack aircraft.  The J 8 design took the J 7 fighter as its starting point, but had a longer fuselage to accommodate a tail gunner, and larger wings.  The prototype flew in late 1917 and was followed over the next few months by three more development aircraft.  The "Idflieg" was sufficiently impressed to want to order the type, but had misgivings about Junkers' ability to manufacture the aircraft in quantity and considered asking Linke-Hoffmann to produce the type under licence.  Finally, however, Junkers was allowed to undertake the manufacture as part of a joint venture with Fokker, producing a slightly modified version of the J 8 design as the J 10.  Like the other Junkers designs of the period, the aircraft featured a metal framework that was skinned with corrugated duralumin sheets.  47 examples were delivered before the Armistice, including three built as floatplanes under the designation CLS.I (factory designation J 11).  After the war, one or two CL.Is were converted for commercial service by enclosing the rear cockpit under a canopy.

Piper PA-8: The Piper PA-8 Skycycle was a 1940s American single-seat light aircraft designed and built by Piper Aircraft at their Lock Haven, Pennsylvania plant.  Towards the end of 1944 Piper announced a number of aircraft it intended to build after the war.  One of these was the PWA-8 (Post War Airplane 8).  An aerodynamic test aircraft was built with the name Cub Cycle and it first flew on 27 August 1944 with a small two cylinder Franklin engine.  The Franklin engine was replaced by a 37 hp Continental A-40-3 and the aircraft first flew with the Continental engine on 12 September 1944.  The Skycycle was a fabric-covered mid-wing single-engined single-seat monoplane with a tailwheel landing gear.  The fuselage was produced using a belly fuel tank as used on the F4U Corsair.  The Cub Cycle was scrapped and a similar but new aircraft was built with the name Skycycle.  The Skycycle first flew on 29 January 1945 using the same Continental engine as the Cub Cycle.  The aircraft was further modified in 1945 with a 55 hp Lycoming O-145-A2 engine and designated the PA-8 Skycycle.  No further examples were built.

Supporting paragraphs: Don R. Berlin Curtiss P-40 Warhawk
Answer: The Curtiss P-40 Warhawk