Airlines warn permanent daylight saving time would disrupt flights

A permanent switch to daylight saving time could force carriers into 18 to 24 months of preparation and trigger widespread disruption across flight schedules, crew assignments and aircraft rotations. Airlines for America warns the change would have considerable implications for aviation, especially for passengers trying to connect through domestic and international hubs.

Congress continues to weigh ending the twice-yearly time change. The U.S. House passed the Sunshine Protection Act, H.R. 139, in a 308 to 117 vote to make daylight saving time permanent. The House Committee on Energy and Commerce said the measure would lock in year-round daylight saving time if federal law allowed it. State legislatures have considered more than 800 bills and resolutions in recent years aimed at establishing permanent daylight saving time, according to the National Conference of State Legislatures.

Permanent daylight saving time would ripple through international coordination, airport operations and software systems built around synchronized departure banks and tightly timed connections. Airlines for America warns the change could affect passenger flow, crew scheduling and aircraft scheduling, all of which depend on exact timing across multiple time zones and foreign partners.

A 2008 Government Accountability Office report found the number of flight delays and cancellations had increased 62 percent nationwide since 1998, while scheduled flight operations rose about 38 percent. A study in Collegiate Aviation Review International analyzed daylight saving time transitions and aviation accident rates in the continental United States from 1978 to 2024, using National Transportation Safety Board data.