MIAMI — In the latest Alaska/Delta battle, Alaska announced earlier this month that it will launch flights between Seattle and New York-JFK this September, and Delta struck back with some changes and upgrades coming to flights between Seattle and JFK.

Aside from SEA-JFK being a very long transcon route, it is also a Delta hub-to-hub route. Currently, Delta operates three flights a day between the two cities; one flight is operated with a lie-flat equipped 757-200, and the other two flights are flown with a 737-800.  Meanwhile, Alaska serves JFK’s neighbor–Newark Liberty International Airport–from Seattle, but to some extent, this route has complimented, rather than competed with, Delta’s service as the carrier offered introductory fares of $149 each way and double miles..

Competition for this route will undoubtedly be fierce.  Delta recently lifted the restriction on complimentary Medallion upgrades on the route, setting it apart from its other transcon services from JFK to Los Angeles and San Francisco.

Delta will add additional frequencies between Seattle and JFK in April, using a mixture of 737s and 757s. The aircraft and capacity will vary day by day; days may have flights operated by domestically configured 757s or one of the transcon 757s by a 737-900ER, but the end result will be the addition of a few hundred more seats each way on the Delta side. Clearly Delta has no intention of allowing Alaska to gain much market share on this route.

It’s also worth noting that Alaska is also launching another long route between Seattle and Washington-Dulles.  As with New York, Alaska already serves another airport in the area, in this case Reagan.  But Reagan is distinctly unhelpful for connecting passengers, whereas Dulles provides access to a number of potential codeshare flights with Air France, British Airways, KLM and especially Emirates.