This question refers to a widely publicized Delta Air Lines incident that occurred in September 2023 on a flight from Atlanta to Barcelona. An Airbus A350 had to perform an emergency "U-turn" and return to Atlanta after a passenger experienced a severe bout of "explosive" diarrhea that spread throughout the center aisle of the aircraft. The pilot famously radioed air traffic control describing the situation as a "biohazard issue." While the individual's identity was protected, the event became a global viral sensation due to the sheer logistical nightmare of cleaning an entire wide-body cabin mid-flight. In 2026, this remains a "textbook" example in aviation training for how crews handle medical and sanitation emergencies. It is important to note that this was a medical emergency for a specific passenger and not a systemic issue with the airline itself. Delta handled the situation by deplaning everyone, deep-cleaning the aircraft for several hours, and successfully getting the passengers to Spain on a different plane later that night.