I've heard people say it can be done, but I was curious if anyone here has given it a try?
I fledged my B&G when she was about 7 years old. I actually regret doing it, as she startled and flew away one day when I had set her on a perch outside for a few moments. I got her back - after a week and all my cash savings as a reward, but that is neither here nor there. You want to know the nitty gritty of how some of us folks have done it.
First off, learn from my mistake, get your sweetie to come to you when you call for her. If she is on her gym or the top of her cage and you can get her to come to you on request, you are set and ready to consider giving her more freedom. Also, stop clipping her flight feathers and let her claws grow a little longer than usual. She will need both if she wants to land on anything other than you.
I started teaching Bubbles to fly by encouraging her to flap her wings. When I'd hold her and she'd start flapping (as they do) I'd lift her high above my head and say something encouraging and consistent. My queue word was simple: "Flap Flap Flap". After a few weeks of successfully teaching her that "flap flap flap" meant we were high up and it was okay to madly flap our wings, I would take her outside and do the same. (you might want to be smarter than me and try an enclosed space like a REALLY large room or a gym. Maybe even a warehouse).
Eventually, when she was
calm when outside under all circumstances (dogs barking, cars moving, trucks honking, etc.) and flapping on command above my head, I moved on to running with her. It started with holding her high above my head and just walking forward saying, "Flap flap flap" (my neighbors thought I was amusing, I am sure), and gradually moved on to running with her flapping madly over my head. Once she started extending her body into that iconic straight line that flying macaws adopt when flying, I knew she was ready.
Normally I hold my birds pretty tightly with my fingers over their claws. I do this because it keeps them alive and stops them from accidentally flapping into household object and out of windows, etc. But I started holding her lighter and lighter until one day she just lifted off and we were running together. It felt AMAZING, I am not going to kid you. Once we got to the end of the long driveway outside my home, she landed on me and that was the beginning of the two of us running and flying together for a few good years.
So there you go, that is how I did it.
What makes me regret it, isn't so much the time she flew away into a 100ft eucalyptus tree for a week - obviously I was freaking out and horribly scared that she would fly further away and even starve to death

. No, what is the biggest problem is her startle response to every single thing that upsets her. Even though we clip her wings, she will still straight up LAUNCH herself off her perch and fly into whatever window/screendoor/opening is in front of her. All the way through the house from the back room to smooshing into the kitchen window one time. Needless to say she's a big girl and we have ended up with broken blinds, shredded screens and lots of tchotchkes/dishes/glasses broken from being knocked off of shelves and counter tops. Also - and this is worse than loosing a few household items - she ends up scratching herself and breaking feathers and the potential for harming her delicate yet gigantic bird body is very high. It gives me anxiety just describing this to you.
Regardless, there are different ways to bird and everyone's situation is somewhat different. Your Sunny or your particular situation might be the perfect candidate for flying. Mine certainly wasn't. My B&G is very high-energy and excitable and will occasionally do something crazy if I leave the room where her gym is set up. Not all birds get all wound up when mommy leaves their side - yours might be cool with you having your own life. But it is something to think about while you are installing stronger screens on your windows and sliding glass doors
