As for flight vs clipping, IMO it's a personal choice, and should be done so considering your own circumstances... In some countries, clipping is frowned upon greatly, while in some they may have laws about the size cage the birds are allowed to live in (I love that rule!!!). And yet, in some countries its a common practice to chain a bird to a playstand, gym, or table-top/hanging perch, for sale, and for in the house, thus needing no cage. Parrot keeping around the world is so different in the various countries, and in America we are just starting to slide with flighted birds rather than clipped, and larger cages rather than small... however, there's still plenty of people who clip their birds do to their own circumstances, and others who will continue buying the small cages no matter how small, or how unsafe, or how wrongly built they are for birds. Petstores especially are a bad example of where to find some really bad sized cages, less your lucky to find one that has decent cages.
As far as harness go however, there are three types that are made in the USA, and a third that I've heard about. The first, a flight suit, is also part birdy diaper, so to speak, and covers up much of the birds body, not including head, wings, or tail. Most birds do not enjoy a flight suit however many can learn to wear them. Some people do not like how the suit connects in the back....
Here's three girls putting flight suits on a green cheek, a blue crown conure, and an eclectus...
http://youtube.com/watch?v=0rm_Dt8XW54
Next is the feather teather harness, which is similar to a dog harness, and should be able to be put on the bird in two different ways (from my understanding?). It's a pretty simple design, however some birds have learned how to get out of them.
Can't find a video of a feather teather harness, but this one is similar as to how to put it on....
http://www.youtube.com/watch?v=TMgWJHPNDjQ
Then, of course you have the aviator harness, which most people seem to enjoy, especially when they can buy different sized leads.... thus making it the best item bought for their money, even though it is the most expensive one....
http://www.youtube.com/watch?v=DY1qMSUlvZ8
I have a feather teather harness for my mitred conure, as it came with him. The more he wears it the more he gets used to it... otherwise though, if he's inside he wants nothing to do with it...
