U.S. Government grants through the decade allowed improvements to the airfield, and after the outbreak of World War II in 1939 vast new sums were provided for possible military use.

After the December 7, 1941, attack on Pearl Harbor, civil aviation at the airfield was cancelled and the U.S. Navy took over the airport, renaming it Naval Auxiliary Air Station St. Augustine.

Used as a satellite gunnery base in connection with training operations at nearby Naval Air Station Jacksonville, improvements were made to NAAS St. Augustine included additional runway and hangar construction, support facilities and a control tower.

With cutbacks in subsidies the feeder airlines went out of business, and by 1950 the airport, with weeds growing through the cracks in the runway, was seen as a "white elephant" the city could ill afford to operate.

In June 1954, the Fairchild Engine and Airplane Corporation announced it would build an aircraft modification plant at the airport, opening the facility the following year.

Ernie gained notoriety by landing a Piper Cub on the "World's Shortest Runway" a wooden platform on top of a Chevrolet van.

In the mid-1980s, Grumman St. Augustine was tasked with a major military contract for "re-winging" nearly all A-6 Intruder carrier-based medium attack bombers for the U.S. Navy and U.S. Marine Corps.

However, following a fatal aircraft mishap involving a Coast Guard E-2C at Naval Station Roosevelt Roads, Puerto Rico in late August 1990, the USCG E-2C program was terminated, CGAS St. Augustine disestablished and the military facility returned to the control of Grumman.

The Fly-By Cafe opened its doors in 1997 offering a second-story view of the airfield, a menu of aviation-themed dishes, and colorful murals of airplane and airshow memorabilia.

Despite the popularity of these flights, Frontier Airlines suspended air service in 2017, referencing a focus on Jacksonville and aircraft availability in the coming year.

In April 2019, Northrop Grumman was awarded a contract amendment of $3.2 billion from the U.S. Navy for the production of the E-2D Advanced Hawkeye, manufactured in St.

[10] Avelo Airlines expressed interest in launching service to St. Augustine in 2023, but subsequently withdrew after failing to reach a deal with the airport.