Seems like a significant security risk that it is publicly trackable?
I've seen AF1 land at the airport here (Bozeman) -- it flew in to the area at high altitude then circled tightly reducing altitude until final approach. I assumed to reduce the chance of a stinger hit from mountain-men.
As you noticed from AF1, the people who manage the flights of nation-level VIPs are extremely cautious and have a rich, well-informed risk model. You can imagine these airplanes have many countermeasures (SPAR19 is a C-40C, which is a military version of a 737). For all we know it was a decoy plane.
Hiding it from the army is not the point. Who knows if there'd be another maniac with a homemade gun or explosives out there, just like what happened with the ex-PM of Japan.
What's the risk of a plane flying over the Sea above the reach of "simple" weapons is being tracked?
A military-level attack against the third highest representative of the United States is a quite certain way to launch a war, maybe even nuclear retaliation, based on how quickly and well "prove" for attribution is unveiled.
However getting attention is a key purpose of that trip.
When US representative fly to Taiwan secretly it's disabled but whole world was talking about Pelosi going there and China's treats to shoot her down for day or two. Putting that flight for whole world to see is actually more secure than trying to keep it secret.
I've seen AF1 land at the airport here (Bozeman) -- it flew in to the area at high altitude then circled tightly reducing altitude until final approach. I assumed to reduce the chance of a stinger hit from mountain-men.