A V formation is the symmetric V-shaped flight formation of flights of geese

Goose

The word goose is the English name for a group of waterfowl, belonging to the family Anatidae. This family also includes swans, most of which are larger than true geese, and ducks, which are smaller....

, duck

Duck

Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...

s, and other migratory birds

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

. V formations are also used on military flight missions.

Aerodynamics

The V formation greatly boosts the efficiency and range of flying birds, particularly over long migratory

Bird migration

Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 routes. All the birds except the first fly in the upwash from the wingtip vortices

Wingtip vortices

Wingtip vortices are tubes of circulating air that are left behind a wing as it generates lift. One wingtip vortex trails from the tip of each wing. The cores of vortices spin at very high speed and are regions of very low pressure...

 of the bird ahead. The upwash assists each bird in supporting its own weight in flight, in the same way a glider

Glider aircraft

Glider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine. Mostly these types of aircraft are intended for routine operation without engines, though engine failure can...

 can climb or maintain height indefinitely in rising air. In a V formation of 25 members, each bird can achieve a reduction of induced drag by up to 65% and as a result increase their range by 71%. The birds flying at the tips and at the front are rotated in a timely cyclical fashion to spread flight fatigue equally among the flock members. The formation also makes communication easier and allows the birds to maintain visual contact with each other.

Military flight missions

Visual contact is why V formations (and the asymmetric echelon formation

Echelon formation

An echelon formation is a military formation in which members are arranged diagonally. Each member is stationed behind and to the right , or behind and to the left , of the member ahead...

s) are also commonly adopted by flights of military aircraft engaged on a common mission.

The basic flight formation for military aircraft

Military aircraft

A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:...

 in many air forces during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

 was a V formation. In the U.S. Army Air Forces, the most basic formation for bombers was a three-plane "V" called an "element". Stacks of these elements were configured to form a defensive bombing formation called the "combat box

Combat box

The Combat box was a tactical formation used by heavy bombers of the U.S. Army Air Forces during World War II. The combat box was also referred to as a "staggered formation"...

". The standard fighter unit, early in World War II, for the British Royal Air Force

Royal Air Force

The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...

 was the V shaped "vic". This involved one lead plane and two wingmen, with the wingmen flying very close to the sides and slightly behind the lead plane to form the V shape. Typically four vics would fly together one after another to form a squadron. The problem with the vics were the formations were so tight that the wingmen had to constantly be watching the lead plane or risk running into them. This left only the lead plane to search the skies for enemy planes. After many complaints from the British pilots of the vics not being the optimal flying formation, the RAF Fighter Command changed the squadron formation so the fourth vic would weave back and forth theoretically giving them a better field of view. This resulted in the "weavers" as they were called being picked off because the German fighters could attack them and get away before the rest of the squadron could leave formation and be ready for a counterattack. The Germans called these vics Idiotenreihen ("rows of idiots"). Later in the war the RAF Fighter Command abandoned the vic formations in favor of the Finger-four

Finger-four

The "Finger-four" formation , is a flight formation used by fighter aircraft. It consists of four aircraft, and four of these formations can be combined into a squadron formation.- Description :...

 formation that the German Air Force (Luftwaffe

Luftwaffe

Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....

) used.

The V formation is also common in ceremonial flyovers and airshow

Airshow

An air show is an event at which aviators display their flying skills and the capabilities of their aircraft to spectators in aerobatics. Air shows without aerobatic displays, having only aircraft displayed parked on the ground, are called "static air shows"....

flights.