Returning to California, he went to work for the Loughead brothers. Can't pronounce that name? They changed it to Lockheed for that very reason a few years later. During those early years, Northrop was Loughead's only engineer on staff. After a short stint in the Army during World War I, Northrop was furloughed back to Loughead to aid with the construction of Curtiss flying boats for the Navy.
One of the features of the designs that Northrop specialized in was the development of aircraft with a minimum of struts and wires, so common in the aircraft of the day. The Loughead S-1 was Northrop's first design for Loughead, and was full of novel design features, such as wing flaps, folding wings, and a monocoque fuselage utilizing a molded plywood skin.
A decade before it's time, the S-1 was too expensive to compete with the market full of WWI surplus aircraft. This forced the Loughead company to close in 1920.
Northrop took up work with Donald Douglas' company. During that time, he designed a plane on his own during spare time, and tried to find a manufacturer for it. He showed it to the Lockheed brothers, and it became the famous Vega. The Vega was revolutionary. No external struts. No wires. No bracing. A mono-wing airplane with an enclosed cockpit, and the engine faired into the fuselage. The Vega soon became the airplane to own if you were serious about winning races. A series of planes followed, the Alpha, Gamma, and Sirius.
After Northrop started his own company, he was able to concentrate on his unique design philosophies. Several very successful conventional aircraft such as the P-61 Black Widow fighter were produced, but Northrop's true love was the development of flying wings.
As a result of politics, the great flying wing bombers of the WWII were canceled. Not content with merely shutting down the program, the Air Force ordered all aircraft destroyed. All tooling, designs, blueprints, reports, etc. were removed and destroyed. As flying wings were Northrop's passion, their destruction broke his spirit. After the program's cancellation and destruction of the planes, he took little interest in his company, and retired a few years later.
In one of the more satisfying reversals I have read about, the Air Force started development of a new large bomber to supplement the B-1. Northrop Aircraft received the contract to build the B- 2. In a rare show of kindheartedness, the Air Force allowed Jack Northrop's security clearance to be reactivated, and in October 1980 he was brought out to the plant and shown the plans for the new heavy bomber. Although unable to speak due to health problems, his mind was still sharp and he was very pleased with what he saw.
Jack Northrop died in 1981 at the age of 86. His reputation as a quiet, gentle genius survives him through his company and the enduring legacy of his airplanes.