Which country first combined helicopters and landing craft in an LPD-based amphibious force?
Short answerBritain pioneered helicopter assault, but the United States created the recognizable modern combined-arms form.
NotesBritain receives credit for early operational helicopter assault during the Suez Crisis. The question describes a more specific organization using an LPD, helicopters, and landing craft for a combined-arms landing. That package is identified with the American Marine Expeditionary Unit model. Early use of helicopters in amphibious operations preceded the later force organization built around the full combination.