What is the advantage and disadvantage of having birds in a cage and a aviaries?

The advantage to a cage - it's smaller and easier to clean! An inside aviary should be walk in so you can clean it and for bigger birds, more room to spread their wings. I have parakeets in an inside cage, ringneck turtle doves in an outside aviary. Outside I had to be sure the birds were protected by many predators, so that can be a disadvantage, but my doves love the interaction of the mourning doves outside their home and seem to enjoy when the wind blows through, not to mention when they bathe, it's much easier than having to clean up the water they flap out! Hope that helps!