Pete Buttigieg says Transportation Department is working to avoid summer travel disruptions

Just ahead of what airlines say could be the busiest Memorial Day weekend for travel since before COVID-19, Transportation Secretary Pete Buttigieg is sharing how his department is prepping for the potentially record-breaking season.

"We know for sure that there is going to be a very high level of demand, a lot of traffic and a lot of pressure on the system," Buttigieg said in an interview with ABC News.

Amid an ongoing air traffic controller shortage that's been partly to blame for disruptions across the system, Buttigieg said the Transportation Department continues to hire and train controllers even as key facilities remain below targets.

"If you look at the optimal numbers, the numbers we like to be at, it is higher than where we are right now. That's why we're doing so much hiring, and it's why we're pushing to make sure that we get a budget as these negotiations go on [between the White House and Congress] that allow us to continue to pick up the pace on that hiring," he said, referring to current spending talks on Capitol Hill.

Major U.S. airlines are touting their expected passenger numbers and schedules ahead of the holiday weekend. United Airlines said it's preparing for its busiest Memorial Day in more than a decade, expecting to carry nearly 2.9 million passengers.

Meanwhile Delta Air Lines said it's expecting to fly 2.8 million customers over the holiday -- a 17% increase from last year. And American Airlines said it will carry more than 2.9 million customers, operating over 26,000 flights.

Those numbers underline the airline industry's continued bounce-back from its pandemic low even as some service periods have been marred by major flight delays and cancellations.

When asked if he thinks airlines can meet the high demand, Buttigieg said his department has been "pressing" the companies to be more realistic with scheduling and actively supporting those efforts in order to avoid more headline-grabbing meltdowns.

"In the New York airspace, we worked with airlines to permit an approach that would allow there to be larger aircraft, which means more passengers with fewer departures, which can mean less congestion," Buttigieg said.

"There's always a question whether airlines are properly aligning their schedules that they're promising with their resources and staffing that they bring to the table, including enough of a buffer to deal with situations that may come up," he said. "Look, there's always weather, and you have to be ready to absorb those issues and respond and get back to normal as quickly as possible."

After increased delays and cancellations among U.S. carriers last summer, Buttigieg called such disruptions "unacceptable."

Now, the secretary said he's seen "a lot of improvements coming into this year" but it's "no guarantee that summer is going to go well."

"We've been pressing the airlines to do better and better on things that are under their control and collaborating." Buttigieg said.

The Biden administration recently announced it would seek to require airlines to provide consumers with boosted compensation, including meals and hotels, if they are left stranded and it's the airline's fault.

Critics say if the rule is put in place, it would end up passing the cost on to consumers. Buttigieg said he doesn't buy that.

"Look, any time that we do a rule or we try to hold companies accountable, they tend to say this. But we already know that this is an approach that can work because there are many other countries that have rules that require airlines to compensate passengers and also have very competitive airfares," he said.

Heading into summer, negotiations are ongoing between various pilot groups and airlines, with some unions voting to authorize strikes.

While the probability of a pilot strike occurring in the U.S. is very slim, Buttigieg said, "We're urging the parties to come to agreements in each of the areas where a contract is in play and understand that the pilots who are a very essential part of the aviation system expect to be compensated well, and their quality-of-life concerns, too. And airlines need to be able to run their business."