November 11, 1918 is Armistice Day, the day Allied powers signed a cease-fire agreement with Germany, effectively ending World War I. The date is significant to the book because it comes too late to save the characters who have fought in the war.
Paul Baumer and a group of friends join the German Army in 1916 at the urging of their schoolmaster. The boys are only nineteen at the time, and they sign up to fight the war with a sense of excitement and youthful enthusiasm. After two years of enduring the grueling, horrific reality of war, however, Paul is the only one left of the seven classmates who joined up together, and he recognizes that even if he survives, he has been irrevocably changed. Paul has come to understand that a whole generation has been ruined and left, bewildered, and lost. He himself focuses on holding on until the armistice comes, but Paul knows that even if he survives to go back to his old life, he "will be weary, broken, burnt out, rootless, and without hope...(he) will not be able to find (his) way any more".
November 11, 1918 should be significant because it is the day the hostilities end, and to survive until that day would mean that one had survived the war. To Paul Baumer, however, it is meaningless, because his life has already been destroyed, and in the end, it does not really matter that he dies in October, a month short of the end of the war (Chapter 12).