He wrote with great satisfaction of his work with the telephone division and later with the wireless division. Especially he liked his work in the Taunus, the Odenwald and the Eiffel, with its varying, beautiful scenery which pleased the nature-lover in him. Service with the wireless took him to Darmstadt with a battalion from Koblenz, and it was there that he first came into contact with the aviation corps. They had a school there on the parade grounds. He silently planned to join them, but not till June, 1914, was he able to attain his heart's desire, when he was transferred to the school at Halberstadt. In six weeks his training was completed, and on the day before the mobilization he passed his final examination. On August 1st, on his way to Darmstadt, where he was ordered, he visited his parents in Dessau for an hour. After they had pushed through the throng around the station to a quiet nook inside, he made a confession to them. He had not been in the wireless service at Halberstadt, as they had thought, but had instead been getting his training as an aviator. He had kept this from them so that he should not spoil their vacation in the Alps at Hinter-Tux. This loving care was remembered in this stirring moment and he was forgiven. Still they could not help being frightened at the dangerous work he had chosen; his brother Wilhelm had already joined the aviation corps of the German army as observer. But in the face of the tremendous happenings of those days, personal care and sorrow had to be forgotten. So they parted with him, commending him to the care of God, who rules the air as well as the earth.
Though eager to be off to war, he had to be content with staying in Darmstadt and Trier with the reserves. Finally, on the 1st of September, he was allowed to fly from Trier to the enemy's country. His objective was Sedan. On the way, he landed in Montmedy to visit his brother Wilhelm, who was an observer with the aviation section stationed there. He was ordered to stay there for a time, and had the great satisfaction of being united with his brother, for the division commander ordered him to report to his troop. So the brothers had the good luck to be fighting almost shoulder to shoulder in the Argonnes and the Champagne. If it was possible, they were both in the same machine: Wilhelm as observer, Oswald as pilot. Each knew he could trust the other implicitly. So they were of one heart and one soul in meeting the thousand and one dangers of their daily tasks.