My caution was that airports should be humpless. Not necessarily spokeless. Undergrounding is remarkably different than surface engineering, and could easily cost twice the sum a standard aerodrome might. For instance a tunnel can be ten times as expensive as a surface roadway of the same length. Plus all connections to appurtenant services, infrastructure.
Flamboyant Architecture was passe in the thirties, and from whence cometh the Bonds? China's tapped, my friend.
bear, not gopher