7,000 miles - according to Google.
However, flying east from D.C. - there are no straight line routes, unless you fly in air space over Russia, or Syria, or Iran.
The only “safe” route I see would be over Israel, Jordan, Saudi Arabia, U.A.E. or Oman, then north over Pakistan.
I have to think a lot a bad guys would notice Air Force One flying near their neighborhood.
Great circle route wouldnt require too much detour.
Air Force One can refuel in air.