I've known for years that geese fly in a V formation to save energy but what exactly is going on? They are not hidden behind the one in front like the cyclists who are having the air flow blocked. It turns out that the upwash from the wingtip of the one in front provides some extra lift - in other words they don't have to beat their wings as strongly in order to support their weight
https://en.wikipedia.org/wiki/V_formation Upwash and induced drag are technical terms new to me and will need further study.
