Geese and some other migratory birds fly in a V formation for a couple main reasons.  First, the V formation reduces the drag force that each bird encounters compared to the force he would feel flying solo.  In one study, the heart rates of pelicans was monitored.  It was found that a flock of 25 birds in formation can fly 70% farther than a single bird using the same amount of energy.  The second benefit of the V is communication.  All the birds can keep track of their fellow travelers.  This is the reason why I will train my family to move in a V formation when we go to amusement parks, airports or other crowded places.  Not to mention the benefits I will get from drafting off of my family members.  I will be able to walk 70% farther than if I was at Disneyland by myself.  And it would be 70% less depressing than being at Disneyland by myself.