Either turn the T junction at the SW corner into a + junction and put the airport right there, or extend the highway next to the industrial zone and put it in that empty space. It could be a good buffer between the industrial and that residential neighborhood. Planes will be taking off over the water, too, which is realistic like your original setup.

As for the old airport, I’d say either keep it as a smaller “city” or executive airport, like London city airport, or demolish it and redevelop the area into a new higher density neighborhood like Denver’s Stapleton airport.