Sit on the Left side of the plane for the best views on flights from St. Louis to Seattle. Left side wins both ends of the flight. During the cruise over the northern Rockies and into the Pacific Northwest, the left side also tends to offer better views of the Cascades and the Columbia River basin as the flight tracks northwest. Right side has Puget Sound on landing but misses Rainier, which is the signature view.

During takeoff from Lambert St Louis International (STL), sit on the Left side for the best views. Lambert typically departs westbound on runway 30L/30R, so a left-side seat looks south over the Mississippi River and downtown St. Louis. You get a clear view of the Gateway Arch and the river bends before the aircraft turns northwest. Notable sights include: Gateway Arch and downtown St. Louis skyline, Mississippi River and its broad meanders, Forest Park (large urban green rectangle), Cahokia Mounds area across the river in Illinois.

When landing at Seattle Tacoma International (SEA), sit on the Left side for the best views. SeaTac predominantly lands northbound on runways 16L/16R from the south, meaning the aircraft approaches from the south over Puget Sound. A left-side seat faces east toward Mount Rainier and the Cascades, which are dramatically visible on final approach. The right side looks west over the Sound but the mountain views are the clear winner. Notable sights include: Mount Rainier (dominant volcanic cone to the southeast), Puget Sound and its islands, Downtown Seattle skyline to the north, Olympic Mountains on the western horizon.

The flight from Lambert St Louis International (STL) to Seattle Tacoma International (SEA) takes Approximately 4 hours 15 minutes to 4 hours 45 minutes.

The flight tracks northwest over Missouri, Iowa, and South Dakota before crossing the northern Rocky Mountains in Wyoming and Montana. Notable features include the Missouri River crossings in the Dakotas, the Bighorn Mountains of Wyoming visible as a distinct range, the broad Yellowstone Plateau region to the south, the Continental Divide crossing in western Montana, and the Columbia River Plateau in eastern Washington — a vast basalt landscape of coulees and wheat fields — before descending into the Cascades and Puget Sound lowlands.