Chester has continued to be well-behaved, so we’ve let him keep his flight feathers. He flies around, but he lands in places we’ve taught him are safe–windowsills, his play gym, and so on.
He now likes to come out of his cage most days. He’ll typically want to sit with me for an hour or so when I’m working.
Weekends, we’ve been sitting on our back deck with him, by taking his cage outside. Sunlight is good for parakeets: they are tetrachromat and can see ultraviolet, so it helps their mood. Also, when they preen, they spread a chemical from their preening gland on their feathers; sunlight then causes a reaction which produces vitamin D, which they then lick back up next time they preen.
As far as training goes, Chester will now fly to my arm when I call him. He’s also good about being taken back to his cage when necessary.
We’ve purchased a larger cage, a flight cage big enough for 3 budgies. We’re going to get him a budgie friend. Also, a lamp with a daylight bulb for winter, when it’s too cold to spend time outside.