NATIONWIDE (FOX NEWS): Multiple airlines on Monday were experiencing system-wide outages causing anger among travelers.

Southwest and Delta both acknowledged on social media they were experiencing issues with their systems.

“It’s affecting our flights system-wide, and we’re working to see if it’s affecting any other carriers this morning as well,” Southwest wrote in response to a beleaguered flier. “In the meantime, once more information has been made available our Agents at the airport will be happy to disseminate it to y’all.”

Delta added: “I completely apologize, we are currently experiencing a System-Wide Outage we are working diligently to get it back up and running. We do not have a specific time as yet.”

The FAA said in a statement the airlines were experiencing issues “with a flight planning weight and balance program called Aerodata. Mainline operations and regional operations are impacted to varying degrees.”

The agency said United, JetBlue and Alaska Airlines were also affected.

Last week, travelers across the country were experiencing widespread computer outages causing delays across multiple airlines. American Airlines, Alaska Airlines and JetBlue were among the carriers affected.