I use the plastic sided pet taxis for our birds, all I do is attach a perch to the front of it where the metal door is. For larger birds you could use a very large pet taxi or even get a metal dog crate and just put a couple perches in it. During the summer, I like to take the birds outside for some sunlight but ziggy's cage is too big to fit through our door ways without being completely taken apart, so what I do is take our dogs crate(that he never uses lol) and I throw a few perches in there and put her outside in that. Seems like the same could be used for a macaw, although it would be hard to transport something that big unless you have a very large vehicle. You may want to consider harness training as well, that way, when permitted, you could just have him leashed instead of caged, it would make it much easier to take him on outings or even to the vet.
I had a large iguana that I harness trained for that same reason, I did educational shows with reptiles but she HATED the carrier. It got to the point, putting her in her carrier made her so grumpy I almost didn't want to use her in the show at times. I started using a harness and leash and the problem was solved. I should probably throw it out there though, that she wouldn't run away or anything if she wasn't wearing the harness, I just used the harness to make others feel better. Something about her being on a leash made people much less afraid of her lol. I guess it made her look more domesticated.