Alaska Air Group carried the most airline passengers through Seattle-Tacoma International Airport in 2016, though the SeaTac-based airline transported fewer travelers than it did a year earlier.

Rival Delta Air Lines, which has spent millions of dollars adding Seattle flights, increasing its gate capacity and building a new lounge, boosted its passenger traffic through Sea-Tac Airport.

Atlanta-based Delta’s Seattle market share increased a bit while SeaTac-based Alaska’s dropped.

Southwest, United…