This first draft of history is messy. We accept now that the Wright Brothers were the first to achieve powered, human flight, and that they did so on December 17th, 1903. They were hardly the first to experiment with flight, though, and at the time the brother's work was viewed skeptically by many rivals. In the new age of drone flight, video and the internet make success easier to prove, but it's the exact definition of success that's hard to pin down. Today, DHL claimed major progress in drone delivery, joining the ranks of other companies claiming the same.