Traffic at Seattle-Tacoma International Airport ran nearly symmetrical over the three-day capture window from September 1-3, 2025: 1,824 arrivals and 1,825 departures across 3,649 total flights, with 885 unique aircraft tracked. The busiest hour fell at 4 PM PDT, when 250 movements were recorded (122 arrivals, 128 departures). The morning ramp-up was steep, with the 6 AM hour logging 104 flights driven almost entirely by arriving traffic (89 arrivals, 15 departures), and volumes held above 200 movements per hour from 8 AM through 1 PM. The overnight window between 3 and 5 AM PDT was the quietest stretch, dropping to single or low double digits. Los Angeles was the top connecting airport with 123 combined movements, followed closely by Denver (121) and Portland (117). San Francisco (111), Phoenix (104), and Spokane (102) rounded out the upper tier. Vancouver (94) and Anchorage (94) tied further down, with Anchorage showing an asymmetry: 55 departures against 39 arrivals over the period. Approach and departure headings concentrated heavily to the east, south-southeast, and south, with easterly approaches accounting for 413 of the 1,824 arrivals. Altitude data across more than 3.4 million ADS-B position points shows a clear cruise-band concentration between 36,000 and 38,000 feet, the three busiest 1,000-foot bands in the dataset. The average recorded altitude was 18,001 feet, pulled down by the volume of low-altitude approach and departure points. The shortest flight in the capture was a 4.3 nm arrival from Boeing Field lasting under ten minutes; the longest was a 2,617 nm departure to Miami lasting roughly five hours and fifty minutes. One departure bound for Santa Fe Municipal reached 46,875 feet, the highest altitude in the dataset. Aircraft registered in the United States accounted for 789 of the 885 unique aircraft, with Canadian, Latvian, German, and South Korean registrations among the international contingent.