On June 15, 2021, Southwest Airlines (LUV) temporarily halted its flight operations, blaming a system issue that created flight disruptions throughout its network. 

“We are in the process of resuming normal operations after a system issue this afternoon that created flight disruptions throughout our network,” the airline wrote in a statement on social media. “We know many Customers still require assistance and are working to address those concerns as quickly as possible.”

On the same day, the U.S. Federal Aviation Administration (FAA) issued a nationwide ground stop. The authority explained that the decision was taken at the request of the airline and has to last until the company resolved a reservation computer issue. Less than an hour later after the initial announcement, the authority lifted the ground stop. 

“The FAA issued a temporary nationwide ground stop at the request of Southwest Airlines (LUV) while the company resolved a reservation computer issue,” FAA’s initial announcement on social media read. 

The brief reservation computer glitch sent shockwaves to the airline’s flight schedule, as it canceled 566 flights and delayed 1769, according to Flight Aware data. The disrupted flights constitute around 16% (canceled) and 50% (delayed) of the airline’s daily flight operations.

In comparison, the following day Southwest Airlines (LUV) flight cancelation and delay rates were 7% and 8 % respectively.

Massive flight cancelations due to computer glitches are no odd occurrences. Less than a month ago, in May 2021, a technical problem with the Sabre booking system disrupted American Airlines (A1G) (AAL) and JetBlue (JBLU) flights for a few hours. In fact, in the past, all major US airlines suffered similar flight schedule disruptions due to computer problems ‒  a problem which can be very costly even when short-lived. For example, Delta Airlines (DAL) said it lost $100 million in revenue after an outage forced it to cancel 2,300 flights in August 2016. 

The disruption comes as the airline is celebrating its 50th birthday and is offering a 50% discount on certain flights in autumn.