Picky, picky, picky.

This same type of discussion went on around here a week or two ago.

It's a call sign and is whoever is operating the plane, just like flights operated by united airlines are "united [flight number]," which explains "Air Force One," "Navy One," "Marine One," "Army One," etc, etc, with the special one being "Executive One" on a private flight.

There is no magic to the president walking on the plane. I'm sure that they pick up their IFR clearance as "air force one" before he's on the plane.

Here's a link to today's go-around story which is really quite boring and not news.