Arthur Walwyn was my grandfather, the youngest of three Walwyn children who served in the war, and I think perhaps to the chagrin of his elder siblings. His elder brother by a good five years, William, went to officer training, didn't immediately go overseas until 1916 or 17, and Arthur, the youngest brother, wanted to do his part and at the age of seventeen was able to sign up for the Air Force. They had lower age restrictions in that time, and so he was able to sign up, much to his family's horror, and was posted overseas ahead of his elder brother the officer.
Arthur flew over Normandy and over France, doing largely reconnaissance, because in that era there wasn't much bombing or dog fighting, because planes were pretty archaic. You see a picture of him in his plane and he looks like a twelve year-old. But he served with distinction during the war.
On leave, he was able to meet up with his brother and sister, who were also both serving, and miraculously all three of them came home safely with war experiences to tell.