I think this will help also, they have all the articles you asked about.

http://www.birdchannel.com/bird-magazines/bird-talk/default.aspx
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you don't "flight train" your bird. you clip the bird's wings, train it, and then you can think about letting the wings grow out. you do NOT bring an un-clipped bird outside. all it has to do is fly away and not coome back one time and you lost your bird for ever, and the bird dies. generally speaking, this will happen the *first* time you bring your un-clipped flying bird outside!

my female cockatiel is not clipped, so she does not "step up". she sits on my shoulder when she feels like it. i get her to go in her cage by putting millet seeds in her cage, and she will fly to eat it. millet is seeds, but they are so good, birds can get addicted to them! i also make her go inside by pretending to wash dishes, when she goes on my shoulder to watch me and just put my shoulder in the cage and make her go inside that way.

my dad's african grey is not clipped, and we play a game with him. all birds love to play "fetch" — only the human plays the part of the dog. the bird knocks something down from a table, the human picks it up, the bird knocks it down, etc. but ours, because he flies, knocks things out of the air! we throw a ball over his head, he flies up and knocks it out of the air wihth is beak or feet!
he also comes to land on an arm, because my dad holds a sunflower seed and the bird comes to the arm for the seed. this is just a variation of "step up" with a seed, because the arm is too far to 'step up' on, the bird flies! he gets his seed and then half the time winds up put in his cage.

and yet, i tell everyone to clip thier birds wings.
1) most people are too stupid to own flying birds. they leave windows open, or leave clean glass windows and mirrors for birds to fly "through" and break their necks on the glass and die. birds also can fall behind furniture and slide down and break a wing that way, so furniture has to be far enough from a wall that a bird falling behind won't break a wing, OR all the holes need to be plugged up with books (put heavy books all the way to a wall), cloth, or other stuff in the room the bird is in. no ceiling fans, wires for birds to chew on… you really gotta bird-proof a room much better for a flying bird than a clipped one.
2) you NEED to clip the wings to train the bird. our african grey flys through the house, but he lands on the perches that my dad build for him that the bird knows are "his". how come? because that's where we PUT him for the year or so that he cna't fly. if we just released this bird in our house, he'd not have "his" places toland on, he'd be landing on lampshades and knocking things down! once the bird is trained, then letting it fly is a different matter.

i do think flying birds are happier, more confident, and healthier (the grey was panting after flying 2 feet at first, now he is effortless acrobat in the air!). but they are also more difficult. if the grey got into an accident, how can we catch him to bring him to a vet? we can't' towel him, he'd bite a finger off! flying birds are not "tame" as such, but you can have an un-easy understanding with them, mostly involving "food is in the cage, so you have to go inside sometime, you lousy bird!"
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