Fairchild XC-120 Packplane
The Fairchild XC-120 Packplane was an American experimental modular aircraft first flown in 1950. It was developed from the company's C-119 Flying Boxcar, and was unique in the unconventional use of removable cargo pods that were attached below the fuselage, instead of possessing an internal cargo compartment.
Source: Wikipedia — Fairchild XC-120 Packplane (CC BY-SA 4.0)