The White Diamond (2004) on Netflix

Plot summary

Graham Dorrington, an aeronautical engineer, travels to Guyana with an airship he built himself, a helium-filled craft shaped like a teardrop that he means to steer over the tops of the rainforest trees. His destination is Kaieteur Falls, in a part of the country that has been little explored. Twelve years before, a similar expedition into the canopy ended in disaster when the cinematographer Dieter Plage, a friend of his, fell to his death. A filmmaker comes along to record the flights and the forest. Also in the area are white-tipped swifts, which roost in a cave behind the falls, and a diamond miner named Marc Anthony Yhap.