In the opening chapter of The Giver we learn that the year before an airplane flew directly over the community. This is against the rules. We soon learn that the pilot had gotten lost and made an error in flying over the community. We also learn that the pilot was released. (Killed)
The year before The Giver opens, a plane had flown over the community going one way, then, a moment later, going the other way. This had frightened Jonas; it provides the best definition of fear he knows.
He was later told that the pilot had been lost, and was "released" for this. (He was killed for being lost.)
Still later in the book, Jonas learns that the Giver had been involved, giving advice and arguing that the community not shoot the plane down.