Delta Air Lines (DAL) - Get Delta Air Lines, Inc. Report shares hit an all-time high on Thursday after the carrier posted strong second quarter guidance, cheering analysts who expect Delta to outperform peers in the current quarter.

Delta shares closed Thursday at $54.37, up 10,5% year-to-date, after hitting $54.84 in afternoon trading.

On Wednesday, the carrier guided towards a second quarter operating margin between 18% and 19%, up 200 basis points from the same quarter a year earlier, and said second-quarter passenger revenue per available seat mile would gain 2.5%, marking the first year-over-year quarterly unit revenue gain since the fourth quarter of 2014.

"Delta appears to be distancing itself from what we view as the recent investor perception of unachievable guides," wrote JP Morgan analyst Jamie Baker in a note.

Baker suggested that Delta's margin gain underscore United Continental Holdings' (UAL) - Get United Airlines Holdings, Inc. Report failure to produce similar gains.

"We are surprised that Delta's operating margin surplus to United actually expanded to ~680 bps from an average of ~400 bps since Q1:16, with both airlines identifying 2017 as 'a transition year' given recent labor cost escalation," Baker wrote.

TheStreet Recommends

"Should margin results gradually replace RASM as the primary equity determinant, United's lack of turnaround progress (to date) may begin to weigh on shares by year-end if not reversed, in our view," he said.

Deutsche Bank analyst Mike Linenberg said that while Delta's stock price hit an all-time high, its market cap has not, reflecting an aggressive share buyback program.

Delta's market cap is around $40 billion, the highest airline market cap in the world but below the $42 billion market cap achieved during 2015, Linenberg said. Second is Southwest with a $38.3 billion market cap.

Cowen & Co. analyst Helane Becker said she expects Delta unit revenue gains to exceed industry unit revenue gains in the current quarter, reflecting improvement after a power outage shut down Delta's computer system for several days in August 2016.

Becker expects current quarter PRASM to gain between 3% and 5%, with margins between 17.5% and 19.5%. "In 3Q17, Delta faces one of the easiest comparisons among the U.S. airlines," she wrote.

"We anticipate a rotation from United and American into Delta," she wrote. "We believe the rotation already started as Delta has outperformed American and United over the last month."

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.