Investing.com -- Delta Air Lines posted better-than-expected first-quarter results on Wednesday while its outlook for the current quarter fell short of expectations.

Delta shares had already risen sharply before the results were published, lifted along with the broader market by the U.S.-Iran ceasefire announcement, which sent oil prices plunging and boosted airline stocks across the board.

The stock was up more than 12% by 06:41 ET (10:41 GMT).

The Atlanta-based carrier earned $0.64 per share in the first quarter, topping the analyst estimate of $0.61, while revenue came in at $14.2 billion, ahead of the consensus of $13.97 billion. Operating income for the quarter was $652 million, with an operating margin of 4.6%.

"Delta’s results underscore the power of our brand and the durability of our financial foundation. We delivered earnings that were more than 40 percent higher than last year, even with a significant increase in fuel costs and operational disruptions across the industry," said Ed Bastian, CEO of Delta.

"Demand remains strong, and we are taking actions to protect our margins and cash flow. This includes meaningfully reducing capacity growth, with a downward bias until the fuel environment improves, and moving quickly to recapture higher fuel costs."

Looking ahead to the second quarter, Delta guided for Q2 EPS of $1.00 to $1.50, below the Street’s estimate of $1.70, and projected an operating margin of 6% to 8%. The company expects total revenue to grow at a low-teens percentage rate year-over-year.

Guidance assumes fuel at the forward curve as of April 2 and includes a refinery benefit of approximately $300 million, resulting in a projected all-in fuel price of roughly $4.30 per gallon for the second quarter.