Stock futures of major United States airlines traded lower during the premarket session of Wednesday as the FAA system outage persists across the country.

Earlier, the United States Federal Aviation Administration (FAA) declared that its Notice to Air Missions (NOTAM) system had "failed." The agency confirmed that technicians are working to restore the service, and domestic departures will likely be on pause until 9 am.

At 7:37 am ET, airline shares edged lower ahead of Wednesday's open. Southwest Airlines (LUV) fell by 1.88%, selling at $35.53. Meanwhile, United Airlines (UAL) declined by 0.55%, American Airlines (AAL) descended by 0.46%, and Delta Air Lines (DAL) fell by 0.11%.