Question: The Republic P-43 Lancer was a single-engine, all-metal, low-wing monoplane fighter aircraft built by Republic, first delivered to the United States Army Air Corps in 1940, it was considered fast and well-armed with excellent long-range capabilities, until the arrival of which World War II-era American piston-engined fighter aircraft, that had distinctive twin booms and a central nacelle containing the cockpit and armament?

Context paragraphs:
Seversky P-35: The Seversky P-35 was an American fighter aircraft built by the Seversky Aircraft Company in the late 1930s.  A contemporary of the Hawker Hurricane and Messerschmitt Bf 109, the P-35 was the first single-seat fighter in United States Army Air Corps to feature all-metal construction, retractable landing gear, and an enclosed cockpit.

Boeing P-26 Peashooter: The Boeing P-26 "Peashooter" was the first American all-metal production fighter aircraft and the first pursuit monoplane to enter squadron service with the United States Army Air Corps.  Designed and built by Boeing, the prototype first flew in 1932, and the type was still in use with the U.S. Army Air Corps as late as 1941 in the Philippines.  There are only two surviving Peashooters, but there are three reproductions on exhibit with two more under construction.

Republic P-43 Lancer: The Republic P-43 Lancer was a single-engine, all-metal, low-wing monoplane fighter aircraft built by Republic, first delivered to the United States Army Air Corps in 1940.  A proposed development was the P-44 Rocket.  While no world-beater as a fighter, the P-43A had a very good high-altitude performance coupled with an effective oxygen system.  Fast and well-armed with excellent long-range capabilities, until the arrival of the Lockheed P-38 Lightning, the Lancer was the only Allied fighter capable of catching a Japanese Mitsubishi Ki-46 "Dinah" reconnaissance plane at the speeds and heights at which they flew.  In addition, the P-43 flew many long-range, high-altitude photo recon missions until replaced by F-4/F-5 Lightnings (P-38 variants) in both the USAAF and RAAF.

Avia B.35: The Avia B.35 (RLM designation Av-35) was a fighter aircraft built in Czechoslovakia shortly before World War II.  It was designed to meet a 1935 requirement by the Czechoslovakian Air Force for a replacement for their B-534 fighter biplanes.  The B.35 was an elegant, low-wing monoplane with an elliptical wing.  The fuselage was constructed from welded steel tube, covered in metal ahead of and including the cockpit and fabric aft of the cockpit, while the wing was of entirely wooden construction.  Rather anachronistically, the Air Force specified a fixed tailwheel undercarriage for the aircraft, in the hope that this would speed development, as the mechanism for retracting the undercarriage was not yet available.

Curtiss P-60: The Curtiss P-60 was a 1940s United States single-engine single-seat, low-wing monoplane fighter aircraft developed by the Curtiss-Wright company as a successor to their P-40.  It went through a lengthy series of prototype versions, eventually evolving into a design that bore little resemblance to the P-40.  None of these versions reached production.

Bernard 20: The Bernard 20 was a 1920s French single-seat monoplane fighter aircraft designed and built by the Société des Avions Bernard.  Originally displayed as a mock-up at the 1928 Paris Air Show it was a low-wing monoplane based on the Bernard V2 racer.  The prototype powered by a 400 hp Hispano-Suiza 12Jb inline piston engine first flew in July 1929 from Orly.  With its racing inheritance, in 1930 the aircraft flew at a speed of 280 km/h (174 mph).  With the lack of interest by the French authorities for monoplanes the project was abandoned after 18 months of test flying.

Avia BH-19: The Avia BH-19 was a fighter aircraft built in Czechoslovakia in 1924.  It was a low-wing braced monoplane derived from the Avia BH-3 and reflected its designers' ongoing belief that the monoplane configuration was the most suitable for a fighter aircraft.  Initial trials revealed excellent performance, but also displayed control problems and aileron flutter.  Nevertheless, the Czechoslovakian Army was sufficiently impressed to inform Avia that it would order the BH-19 if the problems could be rectified.  The first prototype was destroyed in a crash during speed trials, and the second prototype revealed no better handling than its predecessor.  At this point, the Czechoslovakian War Ministry stepped in and asked Avia to cease its attempts to develop a monoplane fighter.

Curtiss-Wright XP-55 Ascender: The Curtiss-Wright XP-55 Ascender (company designation CW-24) was a 1940s United States prototype fighter aircraft built by Curtiss-Wright.  Along with the Vultee XP-54 and Northrop XP-56, it resulted from United States Army Air Corps proposal R-40C issued on 27 November 1939 for aircraft with improved performance, armament, and pilot visibility over existing fighters; it specifically allowed for unconventional aircraft designs.  A highly unusual design for its time, it had a canard configuration, a rear-mounted engine, swept wings, and two vertical tails.  Because of its pusher design, it was sarcastically referred to as the "Ass-ender".  Like the XP-54, the Ascender was initially designed for the Pratt & Whitney X-1800 engine and had to be redesigned when that engine project was cancelled.  It was also the first Curtiss fighter aircraft to use tricycle landing gear.

Lockheed P-38 Lightning: The Lockheed P-38 Lightning is a World War II-era American piston-engined fighter aircraft.  Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms and a central nacelle containing the cockpit and armament.  Allied propaganda claimed it had been nicknamed the fork-tailed devil (German: "der Gabelschwanz-Teufel" ) by the Luftwaffe and "two planes, one pilot" (2飛行機、1パイロット , Ni hikōki, ippairotto ) by the Japanese.  The P-38 was used for interception, dive bombing, level bombing, ground attack, night fighting, photo reconnaissance, radar and visual pathfinding for bombers and evacuation missions, and extensively as a long-range escort fighter when equipped with drop tanks under its wings.

Bloch MB.150: The Bloch MB.150 (later MB.151 to MB.157) was a French low-wing monoplane fighter aircraft developed and produced by "Société des Avions Marcel Bloch".  It featured all-metal construction, complete with a retractable undercarriage and a fully enclosed cockpit.

Supporting paragraphs: Republic P-43 Lancer Lockheed P-38 Lightning
Answer: Lockheed P-38 Lightning