This is a Douglas AC-47D Spooky, otherwise known as the “Puff, the Magic Dragon”.

It was a large, devastating dangerous aircraft. It was also modified — by mounting three .30 inch General Electric miniguns to fire through two rear window openings and the side cargo door — for close air support for ground troops in the Vietnam War.

How did these planes come to be called “Puff, the Magic Dragon”? From the enemy themselves. They began calling them “Dragon Ships” because “they spewed a stream of red phosphorous tracers that hurtled into [their] VC targets”.

Guns.com