The two VC-25A used in the US Presdential fleet broadcast Mode-S, not ADS-B. Dump1090 will pick them up, but since they are Mode-S, no lat-lon is part of the Mode-S message.its blocked on most systems..
but technically AF1 92-9000 and its twin 82-8000 do broadcast ADS-B, when they are within a controlled airspace close to airports or when landing at civilian sites, else they only have the military ID on.
However I will not mention the relevant hexcodes