• Delta Air Lines has said global economic uncertainty over tariffs is hurting bookings.
• "Growth has largely stalled," CEO Ed Bastian said in the airline's first-quarter earnings release.
• Delta said it would ax plans to grow flight capacity in the second half of 2025 as a result.

Delta Air Lines warned that Donald Trump's tariff plan is hitting the airline where it hurts.

"With broad economic uncertainty around global trade, growth has largely stalled," CEO Ed Bastian said Wednesday in a statement alongside its first-quarter earnings.

"In this slower-growth environment, we are protecting margins and cash flow by focusing on what we can control," he added.

As well as managing costs and capital spending, Delta has decided not to expand its capacity in the second half of the year, it said. It previously planned to grow by around 4%.

Bastian also told CNBC the airline also had to deal with "a really tough weather month in January" and the impact of high-profile accidents.

The airline reported quarterly revenue of $13 billion, with an operating profit of $591 million. It also reported earnings per share of 46 cents, beating analyst expectations.

In premarket trading, Delta's share price briefly rose as much as 3.5% before turning negative.

Delta expects things to improve in the next quarter, with earnings per share between $1.70 and $2.30 on an operating margin between 11% and 14%.

It said total revenue compared to last year could fall 2% or rise up to 2%.

The company didn't reaffirm financial guidance for the full year, citing "current uncertainty."

"We're in uncharted, unprecedented uncertainty when you look at what's happened and the pivot so quickly to this self-inflicted situation," Bastian said of the tariffs in a CNBC broadcast interview Wednesday morning.

"I think we're acting as if we're going to a recession," he added. "I think everyone is going into a defensive posture."

Airline stocks have been sinking since around late February on concerns about demand falling due to economic uncertainty.

Delta is down 39% since the start of the year — while rivals United and American have fallen 41% and 47%, respectively.