Sit on the Left side of the plane for the best views on flights from Seattle to Denver. The left side wins both departure and arrival. During the flight, the left side also tracks closer to the Cascades and later the Rockies as the route curves southeast, offering better views of the mountain terrain throughout the cruise portion over Idaho and Wyoming.

During takeoff from Seattle Tacoma International (SEA), sit on the Left side for the best views. SEA typically departs south on runway 16L/16R, then turns east toward Denver. The left side faces north and east during the turn, giving clear views of Lake Washington, the Seattle skyline, and Mount Rainier as the aircraft climbs and banks. The right side faces west toward Puget Sound initially but quickly loses the interesting terrain. Notable sights include: Mount Rainier to the southeast, Lake Washington directly below, Seattle city skyline to the north, the Cascade foothills rising to the east.

When landing at Denver International (DEN), sit on the Left side for the best views. Denver International sits on the plains east of the city, and aircraft typically approach from the east or southeast on runway 16L/34R or similar headings. A left-side seat on approach from the east gives views of the Denver skyline and the entire Front Range — including Longs Peak, Mount Evans, and the Rocky Mountain wall — spread across the western horizon as you descend. The right side faces east toward the featureless Great Plains. Notable sights include: Denver skyline against the Front Range, Mount Evans and its summit road visible as a snow-capped peak, Longs Peak to the northwest, the broad Rocky Mountain Front Range wall running north to south.

The flight from Seattle Tacoma International (SEA) to Denver International (DEN) takes Approximately 2 hours 20 minutes.

The route crosses the Columbia Plateau in eastern Washington, then the Snake River Plain in southern Idaho — a broad flat lava plain visible from altitude. Over Wyoming, the Wind River Range and the high desert of the Wyoming Basin are visible. The route then crosses into Colorado over the northern Front Range before descending toward Denver.