Such a nice place to fly. Have you been training him in trees? I would suggest teaching him how to climb down from trees. When I first started free flying Manzi, the first problem was that Manzi didn't know how to get down from trees.
Here is a good post on it from another woman who free flies african greys:
I'm not saying you need to free fly your guy, but it might be worthwhile to have him learn the skill of maneuvering through trees. Before free flying Manzi, for months I would let him play in a nearby tree as well. That definitely helped him get more comfortable in trees.