The airport shown on that map was proposed, but never built. Actually, Gar Wood was one of the driving forces behind aviation on the east side, and may have been behind that airport proposal. He was an avid aviator and built a hanger on his property near the river from which to launch his seaplane. There was a seaplane area on the river for years thereafter, with its base by the Gregory boat yard down by Waterworks Park.

Here is an interesting video of activities at the DYC in the 1920s. At the end [[beginning at about the 8:50 mark) is footage of Gar Wood taking off from his estate in his seaplane to fly to his Florida estate.
https://www.youtube.com/watch?v=22S9ox0VHko

The area marked on the map for the proposed airport was later used for military housing during WWII [[it was covered in quonset huts), then for the Nike missile radar station mentioned in the original post, and is now Maheras-Gentry Park.