Airports across the United States are in chaos on Wednesday morning as a major technical glitch has grounded domestic flights across the country, and the disastrous effects could already be spilling over to Canadian air travel hubs like Toronto Pearson International Airport.

The U.S. Federal Aviation Administration (FAA) issued a statement early Wednesday, informing travellers of a glitch in its Notice to Air Missions System, which contains crucial flight operations data, including restrictions and hazards.

Basically, it's not safe to operate mass travel in U.S. airspace with this system offline.

"The FAA has ordered airlines to pause all domestic departures until 9 a.m. Eastern Time to allow the agency to validate the integrity of flight and safety information," the agency statement read.

Cleared Update No. 2 for all stakeholders: ⁰⁰The FAA is still working to fully restore the Notice to Air Missions system following an outage. ⁰⁰While some functions are beginning to come back on line, National Airspace System operations remain limited.

— The FAA ✈️ (@FAANews) January 11, 2023

A follow-up tweet told airline passengers that "The FAA is working to restore its Notice to Air Missions System. We are performing final validation checks and reloading the system now. Operations across the National Airspace System are affected. We will provide frequent updates as we make progress."

Pearson Airport is warning U.S.-bound travellers to check ahead of their flights, as delays are already appearing on the airport's departures board.

Given an FAA system outage, we advise all US-bound passengers to check the status of their flight before heading to the airport. https://t.co/8EcwDAKGfG

— Toronto Pearson (@TorontoPearson) January 11, 2023

The situation continues to develop, and travellers are urged to check the FAA and Pearson Airport's social media accounts for continued updates.