When I first got Max, we clipped her wings. Everything we'd read back then (2001/2002 time frame) said that clipping wings was imperative for the bird's safety. We really didn't know any better and just blindly followed that advice.
After I started doing some more reading, specifically this article, we decided to allow our birds to fly. At that point, we had Max, Calypso, and Ethel, an amazing budgie. Since Max had been properly fledged as a baby, she took to flying instantly. Within days, she could get where she wanted, control speed, navigate unknown places; it was great to see.
Like Max, Ethel was an amazing flyer almost right from the start, despite the fact that she had a tumor that doubled her weight. Talk about strength training!
Calypso is another story -- despite the fact that he has the ability to fly, he very rarely chooses to do so, as in several times a month, and usually when he's trying to get back to his cage.
Daphne can fly, though, like Calypso, she rarely chooses to do so and when she does, is trying to get back to her cage.
Rocky has all of his flight feathers currently, but we'll see how long that lasts. He has not shown any inclination to fly. So far, all his flight feathers do is give him the idea to launch flying attacks on us, which are really jumping attacks but his open wings give him a bit longer of a target range so he can get us from further out.
Beeps is a surprisingly good flyer. Caiques are not known for their flying ability and Calypso bore that stereotype out. However, Beeps completely defies it! He was most likely not fledged and came to us with no flight skills. He'd occasionally fly into walls and make bad landings in the beginning. Even now, after a couple of years of flight under his belt, it appears as though flying takes him much more effort than it does the greys. However, he has mastered the ability to change direction mid-flight and land on precarious perches.
Stella's flight progress was also a pleasant surprise. I think she learned a lot from watching Max. She still isn't as steady as Max is -- she kind of wobbles from side to side mid-flight -- but she can navigate surprise barriers, land wherever she likes, and use flight as her primary mode of transportation.
This post is in response to Pamela's question in the comments from yesterday. I will write more (and actually answer the question) later this week -- hopefully tomorrow -- but I wanted to give my parrots' flight backgrounds so as to not muddy that future post.