Leroy Grumman and others worked for the Loening Aircraft Engineering Corporation in the 1920s, but when it was bought by Keystone Aircraft Corporation and the operations moved from New York City to Bristol, Pennsylvania, Grumman and his partners (Edmund Ward Poor, William Schwendler, Jake Swirbul, and Clint Towl) started their own company in an old Cox-Klemin Aircraft Co. factory in Baldwin on Long Island, New York. All of the early Grumman employees were former Loening employees.  The company was named for Grumman because he was its largest investor.

The company filed as a business on December 5, 1929, and opened its doors on January 2, 1930. Keeping busy by welding aluminum tubing for truck frames, the company eagerly pursued contracts with the US Navy.  Grumman designed the first practical floats with a retractable landing gear for the Navy, and this launched Grumman into the aviation market.  The first Grumman aircraft was also for the Navy, the Grumman FF-1, a biplane with retractable landing gear.  This was followed by a number of other successful designs.

Navy contracts

During World War II, Grumman became known for its "Cats", Navy fighter aircraft, F4F Wildcat and F6F Hellcat, and the less well known Grumman F7F Tigercat and Grumman F8F Bearcat (neither of which saw combat during World War II), and for its torpedo bomber TBF Avenger. Grumman's first jet aircraft was the F9F Panther; it was followed by the upgraded F9F/F-9 Cougar, and the less well known F-11 Tiger in the 1950s. The company's big postwar successes came in the 1960s with the A-6 Intruder and E-2 Hawkeye and in the 1970s with the Grumman EA-6B Prowler and F-14 Tomcat. Grumman products were prominent in the film Top Gun and numerous World War II naval and Marine Corps aviation films. The U.S. Navy still employs the Prowler and the Hawkeye as part of Carrier Air Wings on board aircraft carriers as of 2012.

Manned Spacecraft

Grumman was the chief contractor on the Apollo Lunar Module that landed men on the moon. They received the contract on November 7, 1962, and built 13 lunar modules. As the Apollo program neared its end, Grumman was one of the main competitors for the contract to design and build the Space Shuttle, but lost to Rockwell International. The company ended up involved in the shuttle program nonetheless, as a subcontractor to Rockwell, providing the wings and vertical stabilizer sections.

In 1969 the company changed its name to Grumman Aerospace Corporation, and in 1978 it sold the Grumman-American Division to Gulfstream Aerospace. The company built the Grumman Long Life Vehicle (LLV), a light transport mail truck designed for and used by the United States Postal Service. The LLV entered service in 1986

Long Island location

For much of the Cold War period Grumman was the largest corporate employer on Long Island.  Grumman's products were considered so reliable and ruggedly built that the company was often referred to as the "Grumman Iron Works".

As the company grew, it moved to Valley Stream, New York, then Farmingdale, New York, finally to Bethpage, New York, with the testing and final assembly at the 6,000-acre (24 km²) Naval Weapons Station in Calverton, New York, all located on Long Island. At its peak in 1986 it employed 23,000 people on Long Island and occupied 6,000,000 square feet (560,000 m²) in structures on 105 acres (0.42 km²) it leased from the U.S. Navy in Bethpage.

The end of the Cold War, at the beginning of the 1990s, the reduced need for defense spending led to a wave of mergers as aerospace companies shrank in number; in 1994 Northrop bought Grumman for $2.1 billion to form Northrop Grumman, after Northrop topped a $1.9 billion offer from Martin Marietta.

The new company closed almost all of its facilities on Long Island with the Bethpage plant being converted to a residential and office complex (with its headquarters at 1111 Stewart Avenue becoming the corporate headquarters for Cablevision) and the Calverton plant being turned into an airport that is being developed by Riverhead, New York. A portion of the airport property has been used for the Grumman Memorial Park. Northrop Grumman's remaining business at the Bethpage campus is the Battle Management and Engagement Systems Division, which employs around 2,000 people.