Watch fighters take off from almost any air base in the world and you will notice something: they rarely go alone. They roll down the runway in pairs, climb out together and fly the whole mission as a team of two. In fighter slang, that pair is a two-ship, and the second aircraft is flown by the wingman.

It is one of the oldest ideas in air combat, older than radar, missiles or jet engines, and it is still the basic building block of fighter tactics today.

Two pairs of eyes

The reason is brutally simple. A fighter pilot cannot see directly behind or below his own aircraft, and that is exactly where an attacker wants to be. Two aircraft flying in the right formation can watch each other's blind spots. If someone slips in behind the leader, the wingman sees it, and the other way around.

The idea is as old as air combat itself. On 9 August 1915, the German ace Oswald Boelcke protected his comrade Max Immelmann by shooting down a French aircraft that was pursuing him, one of the earliest recorded examples of what we would now call flying as a wingman. The US Air Force still defines the arrangement in plain words.

The lead navigates, makes the tactical decisions and usually takes the first shot. The wingman holds position, keeps a constant lookout, and backs up the leader. In modern practice the roles are more fluid: either aircraft may engage, while the other supports.

Former US Navy F-14 aviator Ward Carroll on what it takes to be a good wingman.

From the pair to the finger-four

The two-ship really came into its own in the 1930s. German fighter pilots in the Spanish Civil War, notably Werner Mölders, developed the Rotte, a loose pair, and the Schwarm, two pairs flying together in what became known in English as the finger-four. Spread out wide, the pilots could see much more sky and support each other in a fight, while tight, rigid formations of three aircraft were easy targets. By the Second World War, most air forces had copied the idea.

The US Navy found its own answer in the Thach Weave, in which two fighters weave across each other's tails so that any enemy chasing one of them finds itself in the other's gunsight. Different names, same principle: two aircraft that work together are far more dangerous than two that fight alone.

The wingman's dilemma

Being a good wingman is harder than it sounds. A wingman must stay close enough to the leader to support him, while also watching the sky behind both of them. Those two jobs pull the eyes in opposite directions. Colonel Robert Smith, who wrote at length about the wingman's job in the Korean War, described those two duties as mutually exclusive, and was clear about which comes first: a wingman stays with the leader, even at the cost of giving up an easy kill.

That discipline is the heart of it. A wingman who breaks away to chase a kill of his own leaves his leader without cover, and the pair becomes two lonely aircraft.

Two-ships in the missile age

Modern air combat happens at much greater distances, with radar and long-range missiles, but the two-ship has survived. The pair still provides mutual support, sensor coverage and a second shooter. Wingmen today share radar pictures through datalinks, sort targets between them and cover each other while one aircraft is busy with a missile shot. Four-ships, made up of two two-ships, are the standard fighting unit for many air forces.

The newest twist is the drone wingman. Programmes such as the Boeing MQ-28 Ghost Bat and the US Air Force's Collaborative Combat Aircraft aim to put an uncrewed aircraft off the leader's wing. Whether the second aircraft has a pilot or not, the logic is a hundred years old: never fly alone.

Why fighter jets fly in formation, explained.

The job looks simple from the ground. From the cockpit, it is one of the hardest skills a young fighter pilot has to learn.

Here is a short explainer from the Ready Airman channel on what the wingman actually does.

Sources: Wikipedia (Wingman, Finger-four, Thach Weave), US Air Force, Ward Carroll, Ready Airman