CHICAGO, April 18  -- United Airlines CEO Oscar Munoz said Tuesday that his company will not consider firing any employees involved in the passenger dragging incident that happened on its flight from Chicago to Louisville in Kentucky on April 9.

Listing it a "system failure" at a conference call, Oscar Munoz said: "this is a true learning opportunity and will ultimately prove to be a watershed moment for our company as we work harder than ever to put our customers at the center of everything we do."

The Chicago-based United Airlines airline is reviewing policies with regard to handling oversold flights to prevent similar incidents, and talking to some passengers and employees on how the airline can take a more "common-sense approach," Munoz said.

In a statement published on April 13, the airline promised that it will no longer ask law enforcement officers to remove passengers from its flights unless it is a safety and security concern, and will fully review and improve the training programs to ensure its employees put customers first.

United Airlines published first-quarter financial results on April 17, posting its first-quarter net income at 96 million dollars, diluted earnings per share at 0.31 dollars, pre-tax earnings at 145 million dollars and pre-tax margin at 1.7 percent.

last week saw a video going viral of David Dao on social media. The 69-year-old Asian-American physician was violently removed from an overbooked United Airlines flight by security officers to make room for crew members at O'Hare International Airport in Chicago after refusing to give up his seat as requested.