The pilot of a hot air balloon that crashed in Arizona, killing four people, had elevated levels of ketamine in his system, according to an autopsy and toxicology report. The balloon, operated by Droplyne Hot Air Balloon Rides, was carrying 13 people at takeoff, and the pilot, Cornelius van der Walt, did not survive the crash. Investigations are ongoing, and the National Transportation Safety Board released a preliminary report stating that the balloon was descending with a deflated envelope before it hit the ground. Ketamine is a dissociative anesthetic that can cause hallucinations and is not approved for use by pilots. Services by the company have been suspended following the tragic incident.