DC-6 / IcelandairDouglas DC 6 Icelandair airplane model. The Douglas DC 6 was one of the first airplanes to fly a regularly scheduled around the world route. With its higher performance, increased accommodation, greater payload and pressurized cabin, it was a natural evolution of the DC 4. During its 11 year production run, Douglas delivered 704 DC 6s, 167 of them military versions. Although the DC 6 had the same wingspan as the DC 4, its engines helped it fly 90 mph