Korean Air is evaluating both the A320neo and 737 Max for it next generation narrowbody fleet.
"As soon as they come up with a price, we'll look at it, but they don't have a price," said Walter Cho, Korean Air senior vice-president corporate strategy and planning, of Boeing's 737 Max.
Despite being a 737NG operator, Cho said the airline is also considering the Airbus A320neo.
"We don't have bias toward any manufacturer," he said "We just look at everything, whatever fits best in our fleet. We're looking at every possibility."
Korean currently holds orders for 10 130-seat Bombardier CS300 aircraft, the first of which is due for delivery in 2015.
Cho said the order was as much about expanding its fleet with smaller aircraft as it was intended as a message to Boeing, which at the time of the order at the 2011 Paris air show was still deliberating on building a new aircraft or launching a re-engine programme for the 737.
Cho called the CS300 a "sign from Korean Air to Boeing so that they would do a new programme on the single aisle, because they weren't moving back then".
The 130-seat CS300 will join Korean Air's fleet in 2015 and will be the smallest aircraft for the carrier.
According to Flightglobal Pro, Korean operates a fleet of 18 737-800s, 16 737-900s and two 737-900ERs, and holds orders for an additional three 737-800s and four 737-900ERs.