When geese fly in either a V formation or a single line, they are drafting off the one in front in the same way that racecar drivers use each other to pick up speed.
The lead or dominant bird, which is always a female, begins a turbulence wave that helps lift the birds behind her.
The farther back in the flock, the less energy they need to fly.
The lead bird rotates positions with the rest of the formation to prevent exhaustion.
The Wright brothers were inspired by the same principle of flight.