South Korean airline company Jeju Air is in talks with French aeronautic defense and space company Airbus and U.S. airplanes manufacturer Boeing to buy 50 narrowbody jets as it expands a network that includes one of the world’s busiest routes.

The potential purchase is worth around $5.7 billion at list prices.

The purchase price offers Airbus a chance to trigger the defection of a Boeing customer in a key market.

Jeju Air said that it has requested both Airbus and Boeing for estimates for plane purchases to internally review prices.