Another reason why geese fly in "V" formation:

If you had a long flight South, would you want your only view to be the North end of the guy (goose) in front of you?

The military took a lesson from the "V" formation, it allows better visual communication between its members. In a straight line, all you could see is the goose (fighter, bomber, etc) in front of you, but in a "V" you see all the geese in front of you, as well as the ones in the other side of the V.