While the Boeing 747 is now out of production and slowly approaching the end of its time, it has served as an integral part of many airline fleets for decades. While the passenger versions are increasingly rare to spot, the US big three have all operated them in the past. Atlanta-based Delta Air Lines operated several different variants of the 747 until its retirement from the fleet. According to data from ATDB.aero, Delta operated over 30 Boeing 747s for many years.