Domestic geese can fly more than you would expect. My brown chineese female years ago got out of the front paddock (had them up there for weeding that day), circled around the side of my fence to the rear paddock where they stay almost all the time, and with about 10 feet between her and a 6ft fence topped with barbed wire she managed to take off and fly over the fence, keep going across 150ft of the back paddock, and make it over the same fence on the other side.
Clip the feathers if you have any doubt about the goose being able to fly out, just be careful not to clip too much. The feathers are like a dog's nails, there's a quick in there that you can knick if not careful. But most geese have no desire to travel outside their home safe area.