Michael wrote:But for regular transport I think the solid carrier provides more protection. The backpack things I think are just weird.
So if the backpacks are weird, what do you think of parrot strollers?
While I would be willing to take a walk with a bird in a backpack (and if we are talking of taking a walk for the sake of taking a walk (or going hiking), then I would be definitively more partial to the backpack than cat carrier by the way (and this is what I believe Rue was getting at)) than in a stroller - THAT is weird

Flight harnesses aren't for everyone and it might take a while to get your birds use to it so it is always good to have alternatives - while I normally use my converted cat carriers for regular travel involving a car (vet, bringing birds to bird club meetings or to be bird sat at my mom's, etc), I really don't think they are practical when just wanting to go for a walk, where the backpack might be more useful.
Oh and Rue, I think the reason you couldn't find anything was because you were looking for Avian Adventure? I believe the name is
Adventure Pack. I posted the first link it found but it does seem to be for sale on quite a few websites so people, if you are looking at getting it, please shop around.
On the same note, I do have a friend on another forum who swears by her Adventure Pack but she did say she invested some money into making it more secure as she did think it needed a few adjustments (although what they were I cannot say).
As for travel cages - I have one but it's certainly not for everyday travel. If I ever go somewhere for a few days and want to take one of my guys - that cage is what I'll take so I can avoid having to bring along a temporary cage and travel carrier (as I don't like the idea of my birds having to spend a few days in a cat carrier).