The first ligher than air flight was made by the Mongolfier(sp) flyer. A hot air balloon made with wood and paper by the French. It was lifted by a large fire at the base. The first passengers were a duck, sheep and some other animal. At the time, it was belived that the smoke, not the expansion of air was the cause for the balloon to rise.
If I remember correctly, they put the animals in there because they were afraid humans may not be able to handle the effects of flight