American Airlines, Spirit Airlines Cancel Hundreds of Additional Flights as They Struggle to Recover From Disruptions

• Summer storms on Sunday kicked off a wave of cancellations.
• Passengers complained on social media about long hold times at customer service and lengthy waits on board before deplaning.
• A lack of available flight crews at American caused more cancellations on Tuesday.

American Airlines and Spirit Airlines passengers have faced hundreds of cancellations and delays since Sunday, as the carriers struggle to recover from disruptions caused by severe thunderstorms and staffing constraints.

More than 370 flights — or 12% of American's mainline schedule — had been canceled as of Tuesday afternoon and disruptions appeared to be leveling off, according to flight-tracking site FlightAware. More than 120 of those cancellations were due to a lack of crews, while 40 were triggered by bad weather, according to an internal list, which was reviewed by CNBC.

Close to 3,000 American flights were canceled or delayed between Sunday, when thunderstorms struck its Dallas/Fort Worth International Hub, and Monday. Some nine hours of severe weather, including high winds, hail and lightening caused about than 100 American flights to divert, the carrier said. Ground crews can't service planes during lightning strikes because of safety risks, adding to delays.

American said it expected its operation to recover Tuesday.

Spirit Airlines canceled more than 60% of its schedule, or 429 flights, on Tuesday, according to FlightAware, on top of about 500 flights between Sunday and Monday.

"We're working around the clock to mitigate the travel disruptions caused by overlapping operational challenges including weather, system outages and staffing shortages in some areas of the operation," Spirit said in a statement. "In responding to these challenges, Spirit has implemented some proactive cancellations again today to reset our operations."

Seven United Airlines flights and five JetBlue Airways flights were canceled on Tuesday.

Travelers complained on social media about difficulties reaching customer service agents and extensive delays.

"Mother nature isn't playing nicely and many flights in and out DFW are delayed or cancelled," American Airlines tweeted to a customer on Sunday.

Ahead of hurricanes and blizzards, airlines will often cancel thousands of flights to avoid passengers and crews getting stranded at airports. Thunderstorms can be more disruptive for passengers and airlines alike, leading often to rolling delays because they are less predictable.

On top of that, airlines are struggling to staff up to handle a surge in travel demand after urging employees to take buyouts or leaves of absence to cut labor costs in the pandemic last year.

The Transportation Security Administration on Sunday screened 2.24 million people, the most since Feb. 28, 2020.

American had trimmed about 1% of its schedule for the first half of July to handle weather and other disruptions as well as staffing issues.

But American has restored more capacity that some of its competitors like United Airlines and Delta Air Lines.

"And we expect to fly a larger domestic network at DFW this August than we did in August of 2019," American's President Robert Isom said on a quarterly call last month.

More capacity leaves little margin for error during disruptions, analysts told CNBC.

Airlines are not required to provide hotel accommodation or food vouchers for travelers whose flights are canceled, according to the Transportation Department.

"Passengers understand that airlines don't control the weather but the mark of a good airline is how it treats passengers when the chips are down," said Henry Harteveldt, founder of travel-industry consulting firm Atmosphere Research Group and a former airline executive.

More than 1,100 Southwest Airlines flights, almost a third of the Dallas-based carrier's schedule, were delayed on Monday, while 44 were canceled. The carrier said the thunderstorms from Sunday sparked the cancellations on Monday.