Interestingly, reporting at the time made no mention of adding narrow-body plane gates. Example from 2020: https://www.airlinereporter.com/2020/01/sea-tacs-int

Interestingly, reporting at the time made no mention of adding narrow-body plane gates. Example from 2020: https://www.airlinereporter.com/2020/01/sea-tacs-international-arrivals-facility-getting-much-needed-upgrade/ https://www.airlinereporter.com/2020/01/sea-tacs-internation... "The new security corridor along the face of Concourse A will provide eight international wide-body aircraft gates with direct access to the new arrivals facility." The Port of Seattle's own deck from 2014 implies only seven: https://meetings.portseattle.org/portmeetings/attachments/2014/2014_10_28_SM_7b_Supp.pdf https://meetings.portseattle.org/portmeetings/attachments/20... (page 3) By 2018 the Port has decided eight are coming: https://www.portseattle.org/sites/default/files/2018-03/Sea-Tac_Intl_Arrivals_Fact_Sheet.pdf https://www.portseattle.org/sites/default/files/2018-03/Sea-... Maybe they opened a gate in the meantime? This 2014 article talks about an increase of nine: https://airlinegeeks.com/2014/11/16/seatac-airport/ https://airlinegeeks.com/2014/11/16/seatac-airport/ "It will also increase the number of wide-body gates from 11 to 20." So does this 2016 article: https://www.bizjournals.com/seattle/news/2016/09/29/fly-through-sea-tac-airports-international.html https://www.bizjournals.com/seattle/news/2016/09/29/fly-thro... "The new facility will allow airlines to add international flights to and from Sea-Tac by increasing the airport's international wide-body aircraft gates from 11 to 20..." This 2015 one sticks to the "add seven" plant: https://informedinfrastructure.com/15920/port-of-seattle-reviews-designs-for-an-expanded-international-arrivals-facility-at-seatac/ https://informedinfrastructure.com/15920/port-of-seattle-rev... "Nearly double the number of existing gates capable of serving international wide-body aircraft from 11 to 18 gates" By 2019 they're talking about adding eight, but not starting from 11: https://seattlebusinessmag.com/aerospace/more-international-flights-equals-more-congestion-delays-sea-tac/ https://seattlebusinessmag.com/aerospace/more-international-... "... a multilevel complex that will expand the number of gates at Sea-Tac that can accommodate international wide-body airplanes from 12 to 20." So I think they squeezed in a gate before construction started. It's fascinating that over the years apparently nobody knew what the hell the plan was. I guess it's no shock that the end result was surprising.