Postal officials said they have recovered and rerouted about 4,000 pieces of mail that had been aboard an Aeromexico jetliner that collided with a private plane over Cerritos on Aug. 31. A thousand other pieces of mail did not have legible addresses or return addresses. Most of the mail was found in the days just after the collision. No one knows how much mail was on the jetliner, but letters continue to trickle in as residents find them, said Bert Miersma, postmaster for Cerritos and Artesia. Sixty-eight people have been confirmed dead and another 14 are missing and believed dead in the disaster.