Alaska Airlines said Tuesday it has ordered another 23 Boeing 737 MAXs, bringing its total order to 68 MAXs that over the next three years will replace most of the Airbus aircraft in its fleet.

The financial terms Boeing offered would have been difficult to pass up. In an interview, Alaska Air Group chief executive Brad Tilden said the airline will have to pay no additional money for the 13 MAXs it will take next year.

“This does not actually require any capital spending during 2021,” he said.