Final answer:
Churchill's statement referred to the critical role the outnumbered RAF played in protecting Britain from German invasion during WWII, highlighting the debt of gratitude owed to these pilots by many.
Step-by-step explanation:
When Winston Churchill said, "Never in the field of human conflict was so much owed by so many to so few", he was referring to the Battle of Britain where the Royal Air Force (RAF), despite being outnumbered, played a crucial role in repelling the German Luftwaffe and preventing the invasion of Great Britain. This statement highlights the immense contribution and sacrifice of the RAF pilots who defended their country against a much larger enemy force. The phrase encapsulates the gratitude of the British people, and indeed the free world, to these pilots who proved instrumental in maintaining the freedom of Europe and the United States during a critical stage of World War II.