Daedalus left his wings on the altar of Apollo as an offering to the god after the tragic death of his son, Icarus. This act was both a gesture of gratitude and mourning. Daedalus would not want to fly anymore because the loss of his son due to the wings he crafted was a heartbreaking reminder of the consequences of his invention. The wings symbolized his craftsmanship but also the painful loss, so leaving them on the altar was a way to honor Apollo and signify that he would never use them again.