American Airlines president jumps ship to rival United

Scott Kirby, the president of American Airlines, has caused a major shock to the airline industry by leaving the company to take up the same position at rival United Airlines.

The change was announced on Monday afternoon, with Robert Isom replacing Kirby in the role with immediate effect.

The switch spells an end to the former president's 20 year partnership with CEO Doug Parker.

Kirby will go straight into the new role of president at United, having been appointed by CEO Oscar Munoz in what he described as "the culmination of the formation of my leadership team."

"What set Scott apart from the other impressive candidates I considered was his excitement at the passion and enthusiasm he is seeing from all of you over the past few months," Munoz said.

Munoz himself only stepped into the role of CEO for United Airlines last summer, and struggled with health problems which led to a heart attack last year.

"Scott will report to me and have overall responsibility for United's operations, marketing, sales, alliances, route planning and revenue management," he added.

American were less forthcoming on the reasons for Kirby's departure, citing the board's "ongoing succession planning process"

"As part of that process, and subsequent conversations regarding career expectations and the marketability of its executives, the company concluded it would not be able to retain its existing executive team in their current roles for an extended period," the carrier said in a statement.