Delta's new Airbus A220 is expanding to more routes and airports this summer, but the state-of-the-art narrowbody jet has been left out of its largest major hub: Atlanta. The A220 debuted in February from Delta's hub at New York's LaGuardia airport to its growing operation at Boston Logan International, and from LaGuardia to Dallas/Ft. Worth. More recently, the airline expanded its A220 routes at Salt Lake City International Airport in April and Mineta San Jose International Airport in May. This week, it launched from Delta's Seattle hub when it began operating on two of Delta's six daily flights to San Jose, with more Seattle routes planned later this year.