I am trying to figure out which idea you recommend forgetting? The covered aviary? It's sounding like pinioning would probably be a good idea? I wouldn't mind just turning them loose here, but state laws prohibit that. We get Canada geese on our stock pond, now and then I have to herd them and their goslings out of my garden. Once in a while I get hissed at, but if I stare them down and take a few steps in their direction they back off. Even when I got between them and their goslings. The only goose I ever got attacked by is an African cross that I have. As a yearling it started hissing when I went in to feed, then one day it came up and bit me. The next time I went in to feed, I hurried up and dumped the feed for them, then when the goose came at me I flipped the bucket upside down over the goose. Then while it was under the bucket, I hammered on the sides a bit. It never came after me again.Full wing "wild" geese do not have to run to take off. They can and will jump straight up and with a hard down stroke of the wings be in full flight. You must clip, pinion, or build a large, fully enclosed aviary. Geese kept full wing in an aviary have been known to hurt themselves by flying into the top or sides. I recommend re-considering that idea.
I would like to fence off a large section of my front yard to give them space in the summer, but don't want them to be able to fly out. How much space do they need to take off? Would it be a good idea to run a few strands of tape across to make a sort of baffle so they can't take off?