It seems you can schedule a Hangout, but not an On Air Hangout. Of course, that's the type we want.
But no fear! We've figured it out. We'll schedule an event, and in the details of the event, we'll say to check back at the time of the event to find a URL.
Then, about 10 minutes before the event, we'll start an On Air Hangout, grab the URL and dump the URL in the details of the event, plus a few other places. That should do it!