In particular, a Boeing KC-135 from the Michigan Air National Guard refueled four A-10 fighter jets over Latvia and four F-16 jets over Estonia. In order to promote cooperation capabilities, two Mirage jets acted as the belligerents in the scenario.
On the outside, the Boeing KC-135 is little different from a regular passenger jet, as it's built based on Boeing 707 designs. It carries about 81 tons of fuel, but the exact volume depends on different circumstances.
During refueling, the jets fly with a speed of a little over 600 km/h, and the jets are separated by just nine meters of air.
The refueling operation took place at a height of about six kilometers, as there's little turbulence that high above.
The US-led Saber Strike 2018 takes place June 3 to 15 across the Baltic states and Poland. It involves more than 3,000 troops from 13 countries. The exercise coincides with several other maneuvers, including Lithuania's Thunder Storm and NATO's Baltops.