A cargo aircraft (also known as freight aircraft, freighter, airlifter or cargo jet) is
a fixed-wing aircraft that is designed or converted for the carriage of cargo
rather than passengers. Such aircraft usually do not incorporate passenger
amenities and generally feature one or more large doors for loading cargo.
Freighters may be operated by civil passenger or cargo airlines, by private individuals or by the armed forces of individual countries (for the last see military
The World War II German design, the Arado Ar 232 was the first purpose built
cargo aircraft. The Ar 232 was intended to supplant the earlier Junkers Ju 52
freighter conversions, but only a few were built. Most other forces used freighter versions of airliners in the cargo role as well, most notably the C-47 Skytrain
version of the Douglas DC-3, which served with practically every Allied nation.
One important innovation for future cargo aircraft design was introduced in
۱۹۳۹, with the fifth and sixth prototypes of the Junkers Ju 90 four-engined military transport aircraft, with the earliest known example of a rear loading ramp.
This aircraft, like most of its era, used tail-dragger landing gear which caused
the aircraft to have a decided rearward tilt when landed. These aircraft introduced the Trapoklappe, a powerful ramp/hydraulic lift with a personnel stairway
centered between the vehicle trackway ramps, that raised the rear of the
aircraft into the air and allowed easy loading.