Behold, the actual plane used. Tail number 09-0017 as shown in the flightaware database. As your screen cap shows, an aircraft's tail number is substituted for the call sign when no call sign is assigned. PF's know this is very common.
What is uncommon, is for a presidential flight not to carry the AF1 callsign.
What is confusing for non Planefags (i.e. most of the MSM and twitterverse), is why this blue and white plane is not the same blue and white 747 commonly seen. I'm exhausted trying to explain it. The USAF has a bunch of smaller transports, commonly used for the vice president and other VIP's. Coincidentally they can land and take off from shorter runways than the 747.
K