The history of aviation in Maryland dates back to the Wright Brothers' first Army aviation school that taught the first two Army officers to fly at College Park. In 1920 Logan Field became the first commercial aviation facility in Baltimore, and in 1941 Harbor Field was opened, and Sikorsky flying boats began regularly scheduled flights.
In 1929, the Glenn L. Martin Company built a factory in Essex/Middle River. For most of the thirties the plant was regarded as the most modern in the U.S. The Martin B-26 Marauder was an outstanding bomber of World War II. A total of 5,266 of these bombers were built.
Baltimore County contributed to that rich aviation history. But over time, all the other Baltimore County general aviation airports have been lost to development. Essex Skypark is the last one remaining. It is truly historic in that respect.
At present Essex Skypark is home to several antique and experimental amateur built aircraft in addition to more modern aircraft. The Chesapeake Model Aircraft Association members fly their model aircraft from a small runway at the airport.
Please review the following link to Paul Freeman's extensive research on the history of small airports in Baltimore County and specifically on Essex Airpark which started life as Diffendahl Airport way back in 1943.