Casper was kept in a small cage for many years before coming to us. We exercise his wings by sitting him on a finger and holding it above our head then swooping down to ground level with the bird hanging on and flapping his wings. If he has had enough before us he flops over backwards on the finger to hang upside down. He's a comedian.
I don't know how practical this is with a much bigger and heavier bird like yours.
He also gets a lot of exercise chasing an empty plastic drinking water bottle around the room on the floor.
In the six years he has lived with us we have only had one scary moment out in the garden. Casper loves to sit in our magnolia tree whilst we sit below reading or in Margaret's case, knitting. On this occasion a neighbour's window caught a gust of wind and flew open causing a bright flash of reflected sunlight. It spooked Casper and he took off over the hedge out of our property, landing on the sidewalk the other side. Fortunately he just stayed put, waiting for one of us to go and fetch him and didn't wander out into the busy traffic.
Casper sleeping in the garden by
Jean-Pierre Declemy, on Flickr