This is a European Hornet, which is very common in our region, and likely a queen. (It's definitely female, as no males exist this early in the season, but whether it's a worker or queen we can't be certain; queens are largest.) Queens begin a new nest by themselves in spring, and eventually when the first worker generation of her daughters is mature, they will take over the duties of building onto the nest and foraging for food. They are not aggressive towards people if a nest is not disturbed or if adults are not swatted or otherwise bothered. You can let her go outside. If you're interested, you can learn more on our Social Wasps web page, which covers hornets, yellowjackets, and paper wasps.

Miri