But port revenue increased by 5.5 per cent to US$222.9 million during the first half of the year compared with the same period a year ago, reports The Seattle Post-Intelligencer.
The seaport saw a slight fall in container volumes, which have fallen 1.4 per cent so far this year compared with the same time last year, but its year on year revenue during the first half rose 2.7 per cent to $53.8 million.
The seaport's capital spending totalled $43 million so far this year, and the seaport expects to spend a further $64.8 million by year's end.
The US Federal Aviation Administration predicted that Sea-Tac Airport's passenger numbers will grow 2.8 per cent each year through 2021, compared to a three per cent growth in domestic flights and a 4.7 per cent growth in international flights through 2020.
The airport has spent $97.6 million on capital projects so far this year, and expects to spend another $230 million by year's end. The airport's total passenger capacity will be between 45 and 50 million when the third runway is completed, the report added.