A United Airlines aircraft sits at a gate at O'Hare International Airport in Chicago. Monday, the company announced it was working on an interim leadership structure to guide the carrier -- the world's second-largest by traffic -- while CEO Oscar Munoz remains in the hospital following a heart attack Thursday. Photo by Brian Kersey/UPI | License Photo

CHICAGO, Oct. 19 (UPI) -- The world's second-largest airline is working on a leadership plan to move the carrier forward in the interim as its chief executive remains in the hospital after a heart attack, a top official said Monday.

United Airlines CEO Oscar Munoz had a heart attack Thursday and has been in a Chicago hospital for four days. In the meantime, the company said it is working to develop an interim leadership structure.


"The company anticipates it will today conclude the corporate governance process necessitated by the hospitalization of President and CEO Oscar Munoz," Chairman of the Board for United Continental Holdings Henry L. Meyer III said in a statement Monday. "The company expects to release more details either later today or tomorrow."

Munoz, 56, had been on the job as United's top executive for a little more than a month when he had the heart attack. The unexpected health issue has led some to wonder how the carrier will handle Munoz's absence.

"In the meantime, the United family's thoughts and well-wishes are with Oscar," Meyer added.

Monday's statement is the first from the non-executive chair of United, the world's second-largest carrier in terms of traffic, regarding Munoz's condition and the airline's immediate plans.

Citing privacy concerns, the airline has not divulged any details about Munoz's exact condition or the circumstances surrounding Thursday's heart attack -- silence that some analysts believe could harm the Chicago-based carrier.

"What the world still needs to hear is exactly what has happened to Mr. Munoz and when -- surely they know that by now even if they don't know yet the likely outcome -- and then what specific 'corporate governance' steps have been pursued as a result," Gimme Credit analyst Vicki Bryan told The New York Times. "United seems to be unwittingly amping up the mounting tension and concern surrounding this already painful episode for Mr. Munoz and his family as well as for United's employees, customers, investors and other stakeholders."

Munoz, who took over United on Sept. 8 after the abrupt resignation of former CEO Jeff Smisek amid a federal investigation, had been preparing to host his first quarterly earnings call scheduled for Thursday.

Shares of United Continental Holdings (Nasdaq: UAL) have lost more than a dollar since Munoz was hospitalized.