I'm sure AF1 is a (Take Charge and Move Out) TACAMO aircraft with a press section. Another possible advantage for a 747 is the 4 engines. The company I work for operates 777s. We've seen an engine gearbox loose all of it's oil. At that point, you look for a place to land. I'm guessing a 747 with one engine out still has the range redundancy and power generation capacity to do what it does. You can't just dump the POTUS any old place. We did have one of ours spend a few weeks at Shemya Island (very last airfield on our side on the Aleutian Island chain) after an emergency landing maybe last year? You probably don't want to risk landing the POTUS some place like that. Again, what are you gonna put him in? I see the 747 as a clear winner.
This article simply exposes the uninitiated 'reader' to the superficial elements of AF1.
NOW, Try to visualize a dressed-up E-4B [747-200B]... NOT the MUCH smaller E-6B [which is actually a dressed-up 707-320]... Command Post Acft... and then try visualize what is under/behind every panel, carpet, bulkhead, the cockpit/upper-deck, wings, engines and stabilizers and wheel-wells. Ughhhh...
Now 'harden/make-redundant' every critical element: structures, engines, mechanical/electrical/electronic system to survive: CME, EMI, EMP, TREES, lightning, corona, ionizing-gamma-microwave radiation, thermal [heat] radiation [+800F], shock-wave blast/overpressure. AND have fuel tank 'inerting' systems and other MIL-grade fire/explosion suppression elements. AND have defensive-countermeasures for every other land-sea-air threat... radar or multispectral [or combination]... against attacking aircraft or guided AAMs, etc. OH... and survive sudden cabin depressurization events.
NOW add in redundant/secure electronics, computing, communication that is resistant to jamming/spoofing and has counter-jamming capability across the electromagnetic spectrum. OH and even the paint like likely a special low IR reflective coating system... and high thermal resistance.
OH... and have a dedicated supply/logistics system for support/repair... along with specially trained electro/mechanical technicians... including tech data for troubleshooting and maintenance, for every element of the aircraft. AND dedicated simulators for the cockpit crews and upper-deck combat crews.
Shallow vision/shallow thinking about AF1 makes converting the Q747-X to AF1X easy-peasy. On-the-other-hand all this could be made so much easier easier IF the Air Force isn't allowed any technical input on the modification; AND if a third party engineering and maintenance/modification shop 'magically' has the full rights and privileges to the Boeing engineering, drawings and manuals for that particular Q747-X aircraft. Hmmmm probably NOT.
But then, what could I possibly now about these crazy-modified aircraft [VC-25A, E-3C, E-4B, E-6B, E-8A]?