How does UA find out about special events that cause high demand and allow for adjusting of fleet allocation or frequencies?
Airlines have people that track major events -- sporting events, conventions, ....
I'm sure many of you know that this August 21, there will be a solar eclipse that passes through Jackson WY. ...
and significant more than just Jackson Hole,
the path goes coast to coast USA and greatest duration is much farther east -- Southern Illinois, Western Kentucky, St. Louis, MO. No particular reason for UA to focus on JAC versus many other locations. Multiple UA serviced airports are in the path.