The tandem-rotor heavy lifter, in service continuously since 1962. Live CH-47 Chinook positions.
The Chinook has no real competitor in the West. Two large rotors turning in opposite directions at each end of the fuselage mean it needs no tail rotor, generates enormous lift, and can load through a rear ramp at the same height as a truck bed — a combination nothing else offers.
It has been in continuous production since 1962, which makes it one of very few aircraft still being built more than sixty years after its first flight. Britain, the Netherlands, Germany, Italy, Australia, Canada, Japan, Spain, Greece and others fly it alongside the US Army.
Being a helicopter, it shows up on ADS-B far less than its numbers suggest. Low-level flying puts it behind the horizon for most ground receivers, so the count here is a fraction of what is actually airborne.
A tandem arrangement cancels the torque that would otherwise spin the fuselage, so no tail rotor is needed and all the engine power goes into lift. It also gives a very wide centre-of-gravity range, which matters when loading heavy and awkward cargo.
Since 1962, without a break. Very few aircraft of any kind have managed that; the current CH-47F and Britain's Chinook HC6 share little but the layout with the originals.
Helicopters fly low, and ADS-B needs line of sight to a ground receiver. An aircraft at a few hundred feet is invisible to stations that would easily hear a jet at cruise altitude.