You know, chap, you may be a German, but you are an airman serving your country nonetheless
Peter Townsend is a young, brand new, RAF (Royal Air Force) pilot, who has to overcome training so he can fly, fight, and most importantly, survive in the battle of Britain during the second world war.
This handshake symbolizes the chivalry between pilots in the war. They rarely met face to face, until after they war, but this changed for our pilot, Peter Townsend, when he hears from a friend and pilot who was shot down, that as the German pilot circled him as he floated slowly toward earth, rather than shooting him, the enemy salutes him, showing respect for an enemy airmen, but an airman nonetheless.
The Climax of the story occurs with an event known as Adlertag, which was the ruthless German bombing of cities in England, such as London. These cites, and there inhabitants are devastated by the bombing, and this in turn, makes the war personal for the British, as their own families may live in said cities.
As the days drag on, this new personality of the war ends up instilling will to continue into the British pilots, allowing them to fight a little harder, downing more enemy pilots as the days go by, while still losing there own. This will to continue is what causes them to fight, and win a little quicker.
Even though Britain kept on fighting, she was still crippled by the German Forces. Hitler knew this, Leading the Germans into a new offensive in a frozen land where no man will stop to let his country die. This land is Russia. With Hitler turning for Russia, the British turn to allies like the U.S., and start an all out purge of Germany. The Allies invade, landing at Normandy, in June of 1944. After this they push on, fighting through Holland, France, and Belgium, with a single goal: Take stop the heart of Germany; Take Berlin. All the while, being supported from above by Townsend and the R.A.F.
The war ended, less than a month later, with Germany's official surrender, on May the 8th, 1945. This would come to be remembered as " VE " day, or victory in Europe day. As the war concluded, Townsend, along with many other pilots, soldiers, or other fighting men, would finally get to go home. As they headed home, the men would remember those, be it there friends, or someone they never knew, who didn't get to go home after the war.