Yep, 43,560 ft. An official soccer field (the grid lined part) is 300 ft x 150 ft, or 45,000 sq ft - or just over an acre.

The large triangle in the overhead view (the one with the two plane-eating trees) looks to be about five acres. I fly a Fighterbird in a nearby park that is basically 250 ft by 400 ft with big sycamore trees on all sides. Depending on the wind the 250 ft approach can be tricky to get it in over the trees and stopped.

By the way, I find the Fighterbird to be a lot harder to control than a "true" gas powered plane with full controls. It is very wind sensitive, and the lack of a proper elevator makes elevation changes something of a juggling act. Takes a lot of body twisting and tongue biting.