WWI saw the birth of an entirely new form of combat: lone men engaging the enemy in aerial dogfights. The victors became heroes back home, but this was as deadly an occupation as it was an exhilarating one. One bullet, an engine or structural failure, or plain bad luck could end a pilot's career in a moment. A flying 'Ace' was a pilot who had accumulated five 'victories', that is, they had downed five enemy planes, airships, or balloons. The 'Ace of Aces' was a pilot who achieved more victories than any other pilot in their nation's air force.

In the early years of the First World War (1914 to 18), airplanes were used largely for patrols and reconnaissance, identifying the positions of enemy artillery and spotting large troop movements. As technology quickly developed, triplanes and biplanes became much faster, more manoeuvrable, and capable of climbing to higher altitudes. Machine guns were mounted at the front of the plane. These guns could be synchronised to fire through the propeller arc, and so the pilot could now attack enemy aircraft. The fighter plane was born, and a new form of warfare developed, where each side tried to destroy the fighters of the enemy, usually in one-on-one encounters known as 'dogfights'. The idea of this more individual form of combat captured the public's imagination, especially as it contrasted starkly with the mass and largely anonymous infantry charges that characterised the trench warfare of the Western Front. Fighter pilots became the most glamorous of all serving men, representing, at least to the public back home, a more exciting and chivalrous form of combat.

The reality of war for fighter pilots was rather different from the public's perception of a quick sortie, shoot down a couple of sitting ducks, and straight back to the mess for a hearty breakfast of bacon and eggs. Pilots (and their gunners in two-seater planes) battled the double risk of highly unreliable machinery and a tenacious enemy fighting for their own survival.

As we shall see, even the very best pilots were throwing the dice of death each time they took to the skies. Not for nothing did some aircraft earn nicknames like 'the flying coffin'. Casualty rates amongst pilots on all sides were at least 50% and many pilots lasted only a few weeks or even days. Death could come at any moment from structural failures, an engine problem, a gun jamming, accidental collisions, enemy fire, or a mistake made from inexperience or fatigue.

As the conflict dragged on, effectiveness and survival in the air war became much more a matter of flying in coordinated squadrons rather than pilots flying as solo knights of the air. It is significant that many of the more enduring air aces were squadron leaders. Enduring success in the air only came when individual skill and bravery were supported by fellow pilots, ground crew, innovative aircraft and weapons designers, and a fair slice of luck.

Early in the war, it was decided that if a pilot shot down five enemy aircraft, then they would earn the title of 'Ace'. As the war went on, technology developed, and the skies became rather more crowded. It was clear that five was perhaps too small a number, but no rigid hierarchy of 'kills'/'hits'/'victories' was ever developed. The methods used to ascertain a victory were often very strict, so probably most aces actually achieved more than they have been credited with. The most revered flying aces were those who managed to shoot down dozens of enemy aircraft and earn themselves such prestigious medals as Germany's Pour le Mérite (Blue Max) and Britain's Distinguished Flying Medal.

Below are the most successful pilots for some of the key nations fighting in the air in WWI. These five men earned the glorious title of 'Ace of Aces' for being their nation's top fighter.

Rittmeister (Captain) Manfred von Richthofen (1892 to 1918), known as the 'Red Baron' for the striking colour of his triplane, was undoubtedly the most celebrated of any fighter pilot during the war. A member of the nobility who first joined a cavalry unit, Richthofen saw that the future of warfare was in the air. Trained and ready to fly by the start of 1916, Richthofen proved a natural and achieved a victory a week for the rest of the year. A ruthless hunter, Richthofen was a devastating combination of fine pilot, tactician, and marksman, typically attacking his enemy by coming at them from out of the Sun.

Richthofen most often flew a single-seat Albatros DI to DIII and then a Fokker DR 1. He painted his aircraft red both as a gesture of intimidation and nonchalance, as this would only make him more visible to the enemy. He led a squadron but was often aloof. When he could, Richthofen kept souvenir trophies of the planes he had shot down; the walls of his room in the family home at Schweidnitz were covered in the cut-out serial numbers and engine parts of his victims. Richthofen won the Blue Max and was presented with it by no less a figure than Kaiser Wilhelm in May 1917.

Richthofen famously commanded Jagdgeschwader (fighter wing) 1 from June 1917, a group of elite pilots that included Manfred's brother Lothar. In the carefree days before camouflage became common, this group of fighters had such an array of brightly coloured Fokker triplanes that it was called by the British the 'Flying Circus'. Jagdgeschwader 1 had no clowns, though, as Friederich Lubbert, who flew with Richthofen, here remembers:

Of course it was a great honour to be in the troop of Richthofen and it was very interesting the first air fight. We were on the French front in the near of Valenciennes and we had air fights with French, Canadian and British air force. One day, we were together with six pilots and four of them shot down ten French and English. And Richthofen alone shot of them four in one day.

(Imperial War Museums)

The Red Baron, after amassing 80 'kills', the most of any pilot in WWI, was himself shot down and killed by a British Sopwith Camel on 21 April 1918. Richthofen, his plane having crashed into Allied-controlled territory near the Somme, was given a military burial. In 1925, the ace's remains were removed, and he was given a lavish state funeral in Berlin, his coffin carried only by holders of the Blue Max.

French Captain René Fonck (1894 to 1953) achieved 75 victories (although Fonck himself claimed he had 127). Fonck served in his country's elite fighter group, the Groupe de Chase No 12, poetically nicknamed Les Cigognes or 'Storks'. Only just managing to convince his superiors that he would be best employed as a fighter rather than a reconnaissance pilot, Fonck made an immediate impact when he started flying fast single-seaters. In his first month, Fonck already had four victories. In a single day in 1918, the Frenchman shot down six planes, a record never matched by any other pilot.

A cautious planner, Fonck studied the tactics of his enemy, constantly practised his sharpshooting, and he not only personally checked his aircraft's machine-guns but even went so far as to check every single cartridge to eliminate the risk of jamming. Fonck was such a good shot that he needed only short bursts to down an enemy aircraft, and so, unlike many other pilots, he very rarely ran out of ammunition. Fonck most famously flew a Spad VII, one of the best fighter planes of the war, and he did so with such effectiveness that he eventually won medals from four different countries. The greatest prize of all, perhaps, was that he was one of the few top aces to survive the war.

British Royal Flying Corps pilot Major Edward 'Mick' Mannock (1887 to 1918) managed 73 victories and was Britain's top flying ace. Mannock began the war in the Royal Engineers but then concealed a sight defect in order to become a flyer from April 1917. Mannock's first 'hit' was an enemy observation balloon, and he soon racked up enough victories to win the Military Cross medal. Mannock was another one who believed in meticulous preparation before sorties, and he was a staunch believer in the advantages of formation flying.

Mannock most famously flew a Nieuport Scout and, from the spring of 1918, a Royal Aircraft Factory SE5a. The latter was one of the war's best single-seat biplanes, and, coupled with the pilot's skill and superior tactics, it allowed Mannock to achieve an astonishing 39 victories in a three-month period, including three in a single dogfight.

Mannock remained undefeated in the air but was shot down by German troops firing from the ground in July 1918. The major was posthumously awarded Britain's highest military medal, the Victoria Cross.

Godwin Brumowski (1889 to 1936) flew for the Austro-Hungarian air force, and he achieved 40 victories on the Austrian-Italian front. Brumowski famously sported a large white skull on a black background on the side of his aircraft, which was then adopted by the unit under his command, Fliegerkompanie 41. Brumowski scored most of his victories flying a German Albatros DIII. A rare survivor of the conflict, Brumowski continued to fly for the air force of the newly created Austrian Republic.

Francesco Baracca (1888 to 1918) flew for the Italian air force and achieved 34 victories. He had a vast flying experience, accumulated even before the war had started. Baracca flew a Nieuport 11 single-seater fighter in 1916 and then moved on to the far superior French Spad VII. His aircraft were always emblazoned with Barracca's personal insignia, a black prancing horse on a white background. The horse was a homage to his youthful days in the Italian cavalry. A squadron leader from the spring of 1917, Baracca's success continued, helped by an upgrade to a Spad XIII, one of the fastest fighters available. Assisting at the Battle of Piave in June 1918, Baracca was shot down and killed by enemy ground troops later that month.

Such was Baracca's success and influence on the early Italian air force, his prancing horse emblem was adopted as the insignia of a flying unit and is still used today (with wings) within the coat of arms of the Aeronautica Militare. After the war, Baracca's black prancing horse was also adopted as the logo of Ferrari sports cars.