Latin American carrier Avianca-TACA has signed a memorandum of understanding for 51 Airbus A320 aircraft, including 33 A320neos.
The airline will use the aircraft to expand into new markets in Latin America.
"Adding the A320neo to our fleet enhances Avianca-TACA's fuel efficiency and range capabilities," said Fabio Villegas, the airline's president and CEO. "Today's historic commitment reinforces our ongoing strategy to provide our customers with the most modern, efficient and environmental friendly services in the region."
The order, when finalised, will be the largest order for the A320neo in the region and also the largest from a single airline for Airbus in Latin America, said Airbus.
An announcement on engine selection is "imminent", said the airline.