During the early years, the company sold its popular correspondence course. The firm grew with the sale of the navigation tools Weems invented.

1930's
The Weems family, along with the company headquarters, moved into the Randall House in the heart of downtown Annapolis in 1939. From there, Weems taught the latest navigation skills to some of the most famous adventurers of this day. Weems mentored and collaborated with Charles Lindbergh, Fred Noonan, former Naval Academy classmate Admiral Richard E. Byrd, and flight pioneer Douglas "Wrong-way" Corrigan.

1940's
Though Weems retired from the Navy in 1933, he was recalled to active duty in 1942 for three years to serve in World War II. The company thrived as a family business and Weems brought several colleagues into the fold including early air navigator Harold Gatty. G. Dale Dunlap joined Weems after the war and played an important role in the long-term success of the company and its offshoots.

1950's - 1980's
Weems System of Navigation was unincorporated until 1952 when Weems (with Dunlap's assistance) started Aeronautical Services Incorporated (ASI) and Weems and Plath, Inc. ASI focused on air navigation markets while Weems & Plath focused on marine navigation. The businesses operated at various locations in Annapolis, including 9 Southgate, 229 Prince George Street, Randall House, 222 Severn Avenue, and in Washington D.C. and Baltimore, MD.