Before the war reconnaissance was regarded as the principal duty of the aircraft of the Military Wing. This was due to two reasons, first, the obvious one that aircraft possessed advantages shared by no other arm for obtaining information quickly and over wide areas and reporting to Headquarters, and second, that experiment had proved the difficulty of loading aeroplanes with offensive weapons, such as bombs or machine guns, without impairing speed and climb.
The following statement, which I drafted and which was issued by the General Staff before the Army Manœuvres of 1912, summarizes the position:—
"As regards strategical reconnaissance," it says, "a General is probably now justified in requiring a well-trained flyer, flying a modern aeroplane, to reconnoitre some 70 miles out and return 70 miles. This would be done at a speed of, say, 60 miles an hour in ordinary weather over ordinary country. Thus within four hours, allowing a wide margin, a report as to the approximate strength, formation and direction of movement of the enemy, if he is within a 70-mile radius, should be in the hands of the Commander."
To those imbued with a knowledge of military history this new method of ascertaining the enemy's movements might well seem revolutionary.
Let us take two instances illustrating what aircraft, with a radius of little over 100 miles, might have done in previous campaigns. For the operations which terminated in the capitulation of Ulm in 1805 Napoleon concentrated two army corps at Würzburg and five along the left bank of the Rhine between Mannheim and Strasburg, his main body of cavalry under Murat being at the latter place. The Austrian Army under Mack was behind the Iller between Ulm and Memmingen, and expected the French to advance through the defiles of the Black Forest, where Napoleon did actually make a feint with his cavalry. Napoleon, however, crossing the Rhine on September 26th, 1805, moved east, and it was not until October 2nd, when the French Army had reached the line Ansbach, Langenburg, Hall and Ludwigsburg, and his envelopment was far advanced, that Mack realized that the main French advance was coming from the north. Aeroplanes of the type we possessed in 1914 could have reconnoitred the whole of Napoleon's preliminary position, could have detected his line of advance, especially as it was concentrated on a very narrow front, and could have brought back the information to the Austrian Headquarters within a few hours.
Aircraft would have been of even greater value on August 16th, 1870, at the Battle of Rezonville, where neither the French nor the Germans were aware of the other's movements. On the 14th a battle had been fought east of Metz which had resulted in the French retreat. On the morning of the 16th Moltke thought the French had retired west by the Metz-Verdun road and those to the north of it, and consequently he directed his left wing due west towards the Meuse to head off the French, sending his right army towards Rezonville to harass their rearguard. The French retreat, however, had been slow and two corps were still at Rezonville, while three corps and the reserve cavalry were within easy reach, some 130,000 men in all. At 9 in the morning the German 3rd Corps, unaided and far from support, attacked a position within reach of the whole French Army, believing it had to deal with a rearguard only. Bazaine, on the other hand, thinking that he was faced by the German main army, remained on the defensive, and lost the opportunity of defeating in detail first the 3rd and then the 10th German Corps. A few aeroplanes operating on a radius of 30 miles would have disclosed between daybreak and 10 a.m. the true position to either commander. Neither the German nor the French cavalry, though both were engaged, obtained any reliable information.
The problem as to how far aircraft would reduce the value of cavalry was widely discussed before the war. It was seen that by day aircraft could obtain quicker and more accurate information, but that cavalry retained their power of night reconnaissance, of mobile offensive action and of pinning the enemy to his ground by fighting. This was found to be so during the retreat, when, in addition to the direct value of aircraft for long-distance reconnaissance, an indirect asset of great importance lay in the release of the cavalry for battle action in assistance of the infantry. The question has become more acute since the offensive action of aircraft against ground targets has developed, but although we must never forget the splendid work of the mounted arm during the Retreat from Mons, and in March, 1918, factors have arisen tending to make the use of cavalry a problem of extreme difficulty in European wars, and it is possible that, in addition to their reconnaissance functions, aircraft will supersede the shock tactics and delaying action of cavalry, though this may be modified if, the sabre being a thing of the past, cavalry are converted into mounted machine gunners.
Air tactics and training were, therefore, chiefly studied from the point of view of reconnaissance. In addition to the possibility of being shot at by other aircraft, an important consideration was vulnerability from the ground. Before the war reconnaissances were carried out at heights varying from 2,000 to 6,000 feet, but it was generally considered that the aeroplane was safe from fire from the ground at heights above 3,000 feet.
Serious difficulties affecting the mobility of aircraft were the means of providing a regular supply of fuel and the selection of landing grounds when moving camp, which had to be close enough behind the front line as not to entail waste of time in flying out and back over friendly territory. This was later brought home to us in a very acute form during the Retreat from Mons.
As machines improved, increasing attention was paid to bettering their power of reconnaissance by air photography, their value in co-operation with artillery by wireless equipment, their offensive action by bomb dropping and their offence and defence by armament.