The two Presidential USAF VC-25As have some of the latest navigation equipment available, triple INS, DNS, GPS, etc. But, the airplanes were originally built with advanced navigation equipment and a Navigator position, sitting sideways, across from the Flight Engineer, and behind the two Pilot positions.
Do the VC-25s still fly with a Nav?
The now retired VC-137B/Cs did have advanced navigation equipment and carried a Navigator, too. IIRC, they carried two Navagators on over water missions and also carried sextants.
The other aircraft, in the presidential fleet, VC-32A/Bs, VC-40Bs, VC-20C/Hs do not have a Navigator position. The only other USAF VIP aircraft that still flys with a Navigator are the VC-135Cs.