I am currently reading the Biography of Viscount Trenchard, father of the Royal Air Force, and came across this.
"Few ever encountered Trenchards soft side - most would probably deny he had one - but Donald Clappen, a private in the London Scottish Regiment, did.
A week before the battle of Loos, he had gone to watch RFC machines take off and land at an aerodrome near Auchel while his battalion was resting behind the lines. Mad keen on flying, he had qualified as a pilot at the age of 18 and before the war had worked as an apprentice at the Bleriot factory in Hendon and had applied to join the RFC several times, without a response.
As I stood watching the machines landing a General emerged from a tent, and acting on the spur of the moment I asked if I could speak. He looked round, astonished and didn't say anything so I pulled out my papers, explained my story, that I was a qualified pilot and wanted to join the RFC. In a very deep voice, he told another officer to make a note of what I had said. The General then called for transport to take me back to my battalion.. I saluted smartly and later asked the driver who he was. He said I had a nerve approaching him because it was General Trenchard!
Clappen later went "over the top" twice and survived the battle of Loos. A month later he received a telegram telling him to report to the War Office and three weeks later was in the RFC. He eventually rose to the rank of Air Commodore."