United Airlines Grounds Airbus A321neo Fleet Due to No Smoking Sign Issue

United Airlines grounded its new Airbus A321neo planes due to a 1990 law requiring manual operation of the "No Smoking" sign, which the aircraft's continuous software doesn't comply with. The FAA has allowed United to fly the fleet while evaluating an exemption request. The agency previously approved a similar exemption for other aircraft in United's fleet in 2020. The situation highlights the outdated nature of the law, given that smoking on planes has been banned for decades.