WATCH: Transportation Secretary Pete Buttigieg speaks on FAA computer outage

Transportation Secretary Pete Buttigieg says “safety is going to be our North Star, as always,” following the outage of the Federal Aviation Administration system on Wednesday.

Watch the briefing in the player above.

“In the middle of the night, it became clear that there were still issues in the accuracy of the information that was moving through.” Buttigieg said. “That’s what led to a call, I think, around 5 a.m. for a complete reboot.”

The outage revealed how dependent the world’s largest economy is on air travel, and how dependent air travel is on an antiquated computer system called the Notice to Air Missions, or NOTAM.

Before commencing a flight, pilots are required to consult NOTAMs, which list potential adverse impacts on flights, from runway construction to the potential for icing.

READ MORE: FAA computer outage brings U.S. flights to a standstill as departing planes grounded

The system used to be telephone-based, with pilots calling dedicated flight service stations for the information, but has moved online.

The NOTAM system broke down late Tuesday, leading to more than 1,100 flight cancelations and 7,700 delayed flights by midday Wednesday, according to the flight tracking website FlightAware.

The chaos is expected to grow as backups compound. More than 21,000 flights were scheduled to take off in the U.S. Wednesday, mostly domestic trips, and about 1,840 international flights expected to fly to the U.S., according to aviation data firm Cirium.