Complex sentence: The hot dog maker and the engineer and brakeman all call Gus a hero, and Gus and Sam fly off into the night, but then dawn arises, so they must go back to their homes to sleep, since they are nocturnal.
Split into simpler sentences: The hot dog maker and the engineer and brakeman all call Gus a hero, and Gus and Sam fly off into the night. As dawn arrives, they must go back to their homes to sleep, since they are nocturnal.