Cancellations by United Airlines still impacting passengers at Denver International Airport

Travel in the days leading up to the Independence Day holiday weekend continues to be tricky for some passengers at Denver International Airport. The Federal Aviation Administration says Thursday was the busiest day for air travel in America since the COVID pandemic.

As of 11 a.m., more than 130 flights were canceled and almost 100 of them are from United Airlines.

A United Airlines spokesperson says flights have been affected all throughout this week. It started with severe storms 6 days ago. Airline staffing shortages and what United says have been issues with FAA air traffic control operations have made things worse.

Secretary of Transportation Pete Buttigieg weighed in on this weeks canceled flights, saying on Twitter: "United's disruptions are elevated but moving in the right direction."

Some of the people who had their flights delayed or canceled on Friday told CBS News Colorado they're just trying to get to their final destination for the holidays. 

"I've used United my whole life and this is the worst I've ever seen it. Lack of service, organization, compassion," said Adam Iudiciani on Friday. He's been stuck in Denver waiting to get a flight since Monday.

"(It's a matter of) contingency planning. A billion dollar company you would think has some kind of contingency preparations and it doesn't seem like they have the right people or ... and even higher than just United, not to put it all on them. But a Department of Transportation level, there's a lack of leadership."

 it doesn't seem like they have the right people 

Denver International Airport is expecting more than half a million people to travel through the airport over the holiday weekend. People who are departing from Denver are asked to get to the airport 2 hours before their flight's boarding time.

Customers who have had flights canceled are able to receive a refund if they no longer wish to travel: united.com/en/us/refunds