The Douglas Y1B-7 was a 1930s United States bomber aircraft. It was the first US monoplane given the B- 'bomber' designation. The monoplane was more practical and less expensive than the biplane, and the United States Army Air Corps chose to experiment with monoplanes for this reason. At the time the XB-7 was ordered, it was being tested by Douglas Aircraft as an observational plane.
The Douglas YOA-5 was an Amphibious aircraft designed for the United States Army Air Corps. Although a prototype was built, it did not enter production.
The Northrop Gamma was a single-engine all-metal monoplane cargo aircraft used in the 1930s. Towards the end of its service life, it was developed into the A-17 light bomber.
The Lockheed Air Express was the second aircraft design created by the Lockheed Aircraft Company after its founding in 1927; the type first flew in April 1928.
The Lockheed Altair was a single-engined sport aircraft of the 1930s. It was a development of the Lockheed Sirius with a retractable undercarriage, and was the first Lockheed aircraft and one of the first aircraft designs with a fully retractable undercarriage.
The Douglas C-1 was a cargo/transport aircraft produced by the Douglas Aircraft Corporation for the United States Army Air Service starting in 1925.
The Kokusai Ki-76, or Liaison Aircraft Type 3, was a Japanese high-wing monoplane artillery spotter and liaison aircraft that served in World War II. The Allied reporting name was "Stella".
The de Havilland DH.75 Hawk Moth was a 1920s British four-seat cabin monoplane built by de Havilland at Stag Lane Aerodrome, Edgware.
The Caudron C.109 was a light utility aircraft built in France in the late 1920s.
The Douglas mailplanes were a family of 1920s American single-seat mail planes designed and built by the Douglas Aircraft Company. The aircraft were used to run the main routes of the United States Air Mail service until the introduction of three-engined aircraft in 1928.
The Focke-Wulf A 20 Habicht was an airliner developed in Germany in the late 1920s. It was a high-wing cantilever monoplane with fixed tailskid undercarriage. The fuselage was deep and seated four passengers in a fully enclosed cabin. The type was not bought by the airlines and only a few examples were built.
The Westland Widgeon was a British light aircraft of the 1920s. A single engined parasol monoplane, the Widgeon was built in small numbers before Westland abandoned production in 1929.
The Northrop Delta was an American single-engined passenger transport aircraft of the 1930s. Closely related to Northrop's Gamma mail plane, 13 were produced by the Northrop Corporation, followed by 19 aircraft built under license by Canadian Vickers Limited.
The Northrop XFT was an American prototype fighter aircraft of the 1930s. A single engined low-winged monoplane, it was designed and built to meet a United States Navy order for an advanced carrier based fighter. It exhibited poor handling, and was rejected by the Navy, the single prototype being lost in a crash. A variant, the Northrop 3A, also was unsuccessful.
The Douglas XP3D was a prototype American patrol flying boat of the 1930s. A twin-engined high-winged monoplane, the P3D was produced by the Douglas Aircraft Company to equip the US Navy's Patrol squadrons, but despite meeting the Navy's requirements, the rival Consolidated PBY was preferred owing to a lower price.
The Douglas XO2D-1 was a prototype American observation floatplane of the 1930s. It was a single engined biplane intended to be launched by aircraft catapult from ships of the United States Navy, but only one was built, the production contract going to Curtiss for the SOC Seagull.
The Douglas XT-30 was a proposed American military advanced trainer. It was never built.
The PWS-11 was a Polish aerobatic and trainer aircraft, developed in 1928-1929 by PWS, which remained a prototype.
The Douglas Cloudster II was an American prototype five-seat light aircraft of the late 1940s. It was of unusual layout, with two buried piston engines driving a single pusher propeller. Only a single example was built, which flew only twice, as it proved too expensive to be commercially viable.
The Douglas DC-1 was the first model of the famous American DC commercial transport aircraft series. Although only one example of the DC-1 was produced, the design was the basis for the DC-2 and DC-3.
