Update (8:25 am): The FAA said the system outages have ended.

FAA SAYS AIRLINE SYSTEM ISSUE HAS BEEN RESOLVED

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Update (7:41 am): We're seeing reports that some of the outages have been resolved. Meanwhile, reporters have confirmed that almost every US airline was impacted.

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Flights at airports across the US have been cancelled Monday morning as Delta, Southwest, American, United and Alaska Air all reported widespread system outages, per reports on social media.

The glitch is believed to involve Aerodata, a system that monitors weight and balance issues for planes. Planes that had been taxiing ahead of takeoff have reportedly been forced to return to their gates. Due to the outage, flights aren't receiving clearance to take off. Southwest, United and Delta have confirmed the outages and are posting apologies and explanations to frustrated customers on social media, including this response by Delta.

@Delta flight DL 6210 to Detroit says delayed until 7am...has the tech issue been resolved, or is my app going to tell me it’s been delayed again even further? 😡 — Robert Riley (@IrishDreamTeam) April 1, 2019

Hello Robert. I do see that the flight is delayed until 7am at this time. It is best to get to the airport in time for the flight, just in case it is changed to an earlier time. Thank you so much and our apologies for the delay. Thank you for your patience. TMS https://t.co/6iDGBJRMTU — Delta (@Delta) April 1, 2019

I’m aware. I was early. The fact that @Delta can’t give an update on an outage of this magnitude is mind boggling. If I miss my connecting flight, I expect reimbursement. — Robert Riley (@IrishDreamTeam) April 1, 2019

I’m aware. I was early. The fact that @Delta can’t give an update on an outage of this magnitude is mind boggling. If I miss my connecting flight, I expect reimbursement. — Robert Riley (@IrishDreamTeam) April 1, 2019

I believe this is affecting numerous airlines with their paperwork. TMS — Delta (@Delta) April 1, 2019

There. Has. Been. No. Update. — Robert Riley (@IrishDreamTeam) April 1, 2019

This is with a company that handles the Delta Connection Carriers as well as several other carriers. We have no update here either. As soon as I can get you an update, I will send it to you. TMS — Delta (@Delta) April 1, 2019

The organizers of 'furry convention' warned participants to check their flights before arriving at the airport.

Hey @FurryFiesta #tff2019 furs heading back home today. If you're on the following airlines, CHECK YOUR FLIGHT! They're having major system issues delaying flights: American, Delta, Southwest, United, Alaska Air. — STrRedWolf @ FurTheMore (@strredwolf) April 1, 2019

Could this be some kind of April Fools' Day hack?

This is a developing story...