When war broke out in 1914, it was just 13 years since the Wright brothers had flown their first aeroplane. Air power was not yet an established area of military operations. The British authorities were slow to recognise its potential importance - witness the officer who remarked that the aeroplane would be useless to the army as it flew too fast for anything to be seen from it. Within the space of four years, however, air power had become an integral part of modern warfare.

For most of the war, there was no separate British military branch for air warfare. The Royal Flying Corps (RFC), formed in May 1912, was an army corps whose primary purpose was to make available British air power for the land war. The Royal Naval Air Service (RNAS) performed a similar function for the Grand Fleet.

It was not until 1 April 1918 that the RFC and the RNAS were merged into a separate military organisation called the Royal Air Force (RAF). This limited remit largely confined air power to a supporting role in the First World War.

Pre-war Europeans had been amazed by the sight of 'flying machines' in the skies above the continent. In particular, the large, cigar-shaped airships, known as Zeppelins, came to be seen as harbingers of death and destruction. The number of casualties caused by wartime air raids was relatively small. More people died in one week in London (in October 1918) from the influenza pandemic than from four years of German air attacks on the city. But the air raid symbolised the new vulnerability of civilians in total war. It also presaged the devastation that air power was to cause - with far more destructive weapons - during the Second World War.

'Red Baron

Not all fighter pilots were so loudly celebrated. In November 1917, for example, Allied soldiers in France sent a note to The Times praising the actions of the 'Unknown Airman' who had been killed while defending them from German machine-gun fire near Bourlon Wood.

The First World War was not decided in the skies. Nonetheless, air warfare played a steadily increasing role in the conflict between the Allies and the Central Powers. The practice of dropping leaflets on enemy troops, begun in September 1914 by German planes over the French town of Nancy, was an important part of the propaganda war. Aircraft were deployed for reconnaissance purposes and featured regularly in trench warfare on the Western Front, strafing enemy lines during confrontations such as the Battle of the Somme in 1916. On both the Western and Palestine fronts, air power was an important factor in the Allied advances of 1918.