FORT WORTH, Texas (NewsNation Now) — American Airlines canceled hundreds of flights across the country through mid-July amid a surge in air travel.

“The first few weeks of June have brought unprecedented weather to our largest hubs, heavily impacting our operation and causing delays, canceled flights and disruptions to crew member schedules and our customers’ plans,” American Airlines said in statement to NewsNation Monday. “That, combined with the labor shortages some of our vendors are contending with and the incredibly quick ramp up of customer demand, has led us to build in additional resilience and certainty to our operation by adjusting a fraction of our scheduled flying through mid-July.”

It’s leaving some passengers stranded. Madeline Delgado told NewsNation her flights were delayed multiple times and then cancelled. She’s trying to get to her brother’s funeral.

The cancellations come amid airlines and other transportation operators seeing a quick ramp-up in demand as U.S. COVID-19 vaccination rates increased and travel restrictions lifted in recent weeks.

According to data from the Transportation Security Administration, nearly 50 million airport passengers were registered in May, up 19% from April.

The airline said it “made targeted changes with the goal of impacting the fewest number of customers by adjusting flights in markets where we have multiple options for re-accommodation.”

It takes time for furloughed pilots to get recertified, and there was already a shortage before the airlines shed staff during the pandemic.

“A lot of that is going to come down to spending time in the simulators going through a series of refreshers,” said Glenn Ponas of the Aircraft Owners and Pilots Association. “They will be refreshing their standard procedures and their emergency procedures because those are things they can’t practice while they’re in an airplane. They will spend a lot of time doing that. There’s a lot of checkboxes that have to be marked off.”

Ponas says there are more than 600,000 job openings expected this decade, and encourages anyone curious – especially young people – to think about it.

“Once you leave the ground you never see the world the same,” he said.

This story is developing. Refresh for updates.