Easy Airbus or Boeing?
Some companies like to have one major and one minor supplier. They used the second one to obtain better deals from the first but also they like to have some alternates available.
Easy might earn some advantage from developing a second base, Airbus only, at AI expenses. In that way EZ have a second type in its fleet and is not overdependent on a grounding of the 737. Remember the rudder problems..(Please no A vs B war)
Additionnaly it accumulates Airbus experience and would be more able to take additonal Airbus at a later time if the 737NG fails to perform in the future.
AI wins because it buys a foothold on the low cost segments.
Rwy in Sight