So far, travel this summer has been characterized by long lines at airports, a spate of flight delays and cancellations, and unprecedented amounts of lost luggage. All of which make for one of the most chaotic travel seasons in recent memory.

It’s so bad that Delta Air Lines sent an empty plane to one of the world’s biggest hubs, London Heathrow, just to fly over 1,000 lost pieces of luggage back to the U.S.

This Wednesday, Delta became the first airline to release quarterly earnings, shedding a light on the situation. It revealed some issues bubbling under the surface.

The company is experiencing a “training and experience bubble,” CEO Ed Bastian said in the company’s quarterly earnings call on Wednesday.

Nowhere is this clearer than the gap between staffing and air travel capacity: Bastian reported that Delta had recovered to 95% of the staffing level from 2019 pre-pandemic levels, but the airline was only operating at 82% of air travel capacity. In other words, a nearly fully staffed Delta is operating close to 20% below its peak level. To understand why, you have to go back to the brief pandemic recession of 2020, when Delta was one of several airlines to lay off staff—and accept government bailout money.

2022's summer travel chaos has roots in 2020

The lower air-travel capacity is intentional on Delta’s part, Bastian explained.

“By ensuring capacity does not outstrip our resources and working through our training pipeline, we'll continue to further improve our operational integrity,” Bastian said on the earnings call.

The airline said it had increased staff numbers at airports and in its reservations department, but still had to complete its hiring in pilots, flight attendants, and mechanics. This means that while the company may have been equipped to deal with the increased demand in air travel from a ticketing perspective, it is still ramping up with regards to its actual flights.

On the same earnings call, Bastian said the company has about 1,500 new pilots in training and more “waiting to be trained.” He specified that this number was “larger than we would normally carry.”

When asked about the financial and operational implications of the training backlog, Bastian said it was part of the company’s planned rollout to return to its 2019 flight schedule.

“The good news is that we've got all our folks,” Bastian said. “So, we're at peak with respect to ‘training’ and I wouldn't call it inefficiency but the cost of efficiency. Every month that goes by, it's going to get better.”

In June 2020, a little over two years ago, 2,000 Delta pilots opted to take early retirement as the airline sought to reduce headcount in the earliest days of the pandemic when the number of global flights plummeted roughly 80%. In April 2020, Delta had received $5.4 billion, including a $1.6 billion loan, from a taxpayer-funded airline bailout.