Delta Air Lines faces U.S. investigation over handling of system outage

Delta Air Lines Inc. is under investigation by U.S. authorities over its handling of a technology glitch that has led to thousands of canceled flights.

The Department of Transportation has opened a probe “to ensure the airline is following the law and taking care of its passengers during continued widespread disruptions,” U.S. Transportation Secretary Pete Buttigieg said Tuesday in a post on X.

The decision adds to the strain on the carrier after it said a day earlier that it expected cancellations to stretch later into the week. Delta has fared the worst among U.S. carriers, with most other airlines getting back on track over the weekend after systems across numerous industries worldwide were disrupted by an outage Friday caused by CrowdStrike Holdings Inc.

Delta is “fully cooperating” with the investigation and remains “entirely focused” on restoring operations, the airline said in an emailed statement. More than half of its worldwide IT relies on Microsoft Corp.’s Windows operating system, which was affected by the software error.

The carrier canceled 418 daily flights as of Tuesday morning, or 12% of its normal schedule, according to tracking service FlightAware.com. That pushed its total since Friday’s breakdown to about 5,400 grounded trips.

By comparison, rival carriers American Airlines Group Inc., United Airlines Holdings Inc. and Southwest Airlines Co. combined had canceled fewer than 100 flights Tuesday.

Delta’s problems stemmed from the outage’s impact on an internal system used to process changes to many flights and their crews. That created a cascading effect, leaving Delta unable to get its crews and planes fully aligned.

Its shares fell less than 1% before regular trading Tuesday in New York.

Clough and Schlangenstein write for Bloomberg.