Larry will later describe his own love of flying, saying that it’s the closest he felt, as a young man, to beauty, freedom, and unity with “infinitude.” Patsy seems to have had a similar relationship with flying, but he is also killed while he’s flying. Flying then serves as a concrete symbol of the abstract idea of the “problem of evil.” With that in mind, when Larry asks why evil exists, he could also be asking whether the cruelty and meaninglessness he witnessed when Patsy died while flying tarnishes the beauty he felt moments before, rendering that beauty meaningless in the face of suffering.