United Airlines has distributed 30,000 miles to travelers whose flights were canceled or delayed due to bad weather and air traffic gridlock last week.

Customers who experienced overnight delays or never reached their destinations between June 24 and June 30 received the vouchers, a United representative told CBS MoneyWatch. The 30,000 miles are redeemable for a ticket between more than 8,000 cities in the continental U.S., according to the airline.

The travel hold-ups occurred during what United Airlines CEO Scott Kirby called one of the "most operationally challenging weeks of [his] career."

"Airlines can plan for things like hurricanes, sub-zero temperatures and snowstorms, but United has never seen an extended limited operating environment like the one we saw this past week at Newark," Kirby told employees in a July 1 email.

CEO takes off on private jet

Kirby has faced backlash for chartering a flight on his private jet last week, flying from Teterboro Airport in New Jersey to Denver, Colorado, during the travel disruptions. He later apologized for the move.

"Taking a private jet was the wrong decision because it was insensitive to our customers who were waiting to get home," Kirby said last weekend in a statement. 

More than 40,000 flights arrived behind schedule between June 24 and June 30, and nearly 8,000 were canceled, according to data from flight tracker FlightAware. On Friday alone, roughly 8% of United flights were canceled and 45% were delayed, making it one of the hardest hit U.S.-based airlines. 

Cancellations and delays continue to roil travelers' plans during the Fourth of July weekend, which was on track to be one of the busiest Independence Day weekends for travel in U.S. history, AAA forecasted. As of Monday morning, there were 182 flight cancellations reported in the past 24 hours at Newark Liberty International Airport, one of United Airlines' northeast travel hubs, data from FlightAware shows.

Meteorologists predict rainy weather and thunderstorms will continue to move through the New York metro area on Monday and Tuesday, which could impact more flights. However, the travel disruptions are also the result of aircraft backups at Newark airport, which reduced the number of departing aircrafts at Newark by 60%-75% for an average of 6 to 8 hours each day, Kirby said in his email. 

"Severely limited" capacity

"Airlines, including United, simply aren't designed to have their largest hub have its capacity severely limited for four straight days and still operate successfully," Kirby said.

Staffing shortages at the Federal Aviation Agency, which performs air traffic control duties in the U.S., have aggravated travel disruptions, Kirby said last week. 

Due to that combination of issues, United's leaders are planning to modify schedules at Newark airport. 

"We are going to have to further change/reduce our schedule to give ourselves even more spare gates and buffer — especially during thunderstorm season," Kirby said in his email to employees.

United has not provided additional details about those schedule changes as of publication time. 

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