American Airlines canceled hundreds of flights over the weekend. The airline says a culmination of factors have impacted its operations.

The cancellations come as increased vaccinations and the lifting of travel restrictions prompted a spike in the demand for the airline industry.

A spokesperson for American Airlines said unprecedented weather at its largest hubs heavily impacted operations, resulting in the cancellations, delays and disruptions to crew member schedules.

The company said it was responding by adjusting its flight scheduling through mid-July.

The Sky Harbor airport website shows at least 20 American flights were canceled Sunday and Monday.

According to the airport, more than 4.8 million passengers have boarded flights there in the past four months.