Actually that is one of the things that I would like to know as well and was hoping to get some indication of.
There are many fully flighted birds that don't fly due to having been confined to their cages for so long that their flight muscles have atrophied and some of them are cage bound and even with the cage door wide open never leave the inside of the cage. I have an amazon that it has taken over three years to get her to start climbing around on the outside of her cage because she was never allowed to come out. Even if we are in another room we know when she comes out of her cage and begins her trek around the outside of the cage because despite her knowing that we want her to come out it is still so emotionally traumatizing for her that she screams the entire time that she is climbing on the outside of the cage. Fortunately she is still able to fly, once in a while we can get her to step up and we take her on a walk about the house and sometimes we can get her to hang out with my Lady for a while but when she is ready to go back to her cage she just flies there.
Some bird do not fly inside the house they live in because there is not enough space for them to fly about without a lot of extra effort, my Grey is like that although she is a good flyer.
I hope that this thread will eventually, let people understand that we can talk about this in a ,at least, relatively reasonable manner, time alone will tell.