Routes to and from Florida and Myrtle Beach were cancelled this afternoon at Pittsburgh International Airport.

PITTSBURGH (KDKA/CNN) — Another day of delays and cancellations by Spirit Airlines has stranded thousands of travelers around the country this week.

The changes are taking a toll here in Western Pennsylvania at Pittsburgh International Airport and at Arnold Palmer Regional Airport.

READ MORE: Spirit Airlines' Delays, Cancellations Strand Over 100 Passengers At Arnold Palmer Regional Airport

Routes to and from Florida and Myrtle Beach were cancelled this afternoon at Pittsburgh International Airport.

In Latrobe, however, officials at Arnold Palmer Regional Airport are hopeful that Spirit can bounce back.

“Spirit is really doing the best they can to get back into business, and we’re happy that they are flying in today. We don’t know what the future holds, but they will get it together,” Gabe Monzo, the airport director, said.

The low-cost carrier had canceled more than 40% of its schedule, or nearly 300 flights, as of midday Tuesday, according to the aviation tracking website FlightAware. Another 12% of its schedule was delayed, FlightAware reported.

On Monday, cancellations and delays disrupted 71% of Spirit’s schedule, and Sunday saw 60% of its schedule canceled or delayed, FlightAware said.

The airline told CNN it was proactively canceling flights because of “overlapping operational challenges including weather, system outages and staffing shortages in some areas.”

Pressure on Spirit’s schedule had been building for about a week, a source familiar with the airline’s operations said. Delays, including from multiple thunderstorm systems, had pushed flight crews past the number of hours they may work under federal safety rules.

The scramble to find a new crew for individual flights eventually tapped out the replacement crews’ hours, too.

In the past few days, the issues reached a tipping point, the source said. The airline’s schedulers spent Monday figuring out how to reset the system, rather than deal with day-of turmoil.

The airline said it was “working around the clock” to get back on track.

To check you flight status, visit Spirit’s website here or click here for Pittsburgh International Airport’s flight tracker.

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