After a system outage, FAA is "Back To Normal," but more flights will experience delays.

According to FlightAware, 1,237 domestic flights have been delayed as of 11 a.m. on Thursday, while 104 have been cancelled.

As of Thursday, Delta Air Lines anticipates "little residual impact," adding that it will attempt to reimburse impacted passengers or assist with flight rebookings.

The FAA said in a statement that it is "conducting a thorough review to identify the core cause of" why its Notice to Air Missions (NOTAM) system is malfunctioning.

Despite claims to the contrary from the FAA and Transportation Secretary Pete Buttigieg, it is still unclear what caused the NOTAM system to malfunction.

More flights may be impacted through Friday, according to Captain Chris Torres, vice president of the Allied Pilots Association

Travelers have been urged by certain airlines, including United Airlines, to keep an eye out for potential delays and cancellations in the future.