The pic (click main photo to enlarge) was snapped at the beginning of December somewhere over a desert in the U.S. Central Command’s area of responsibility. That includes countries like Afghanistan, Bahrain, Somalia, Sudan, or Yemen.
For people living in these regions, military aircraft in the sky is a constant occurrence, and the F-16 is one of the most widespread machines in action there – and also all over the world, with more than 4,000 of them made over the years and deployed by many nations.
The KC-135, on the other hand, is a rarer sight, with about 400 currently operated by the USAF to support long-duration missions. Like most other planes of its breed, the Stratotanker is crucial to keeping fighter aircraft in the air long past their natural capabilities.
For instance, the F-16 can fly for about 500 miles (860 km) when configured for air-to-surface combat missions, but lacking any weapons and boasting drop tanks instead, the range drastically increases to 2,600 miles (4,200 km).
Technically, aerial refueling could increase those numbers to the point of, well, infinity, if it weren’t for the physical limitations of the pilot and the uselessness of such a flight.