Sit on the Left side of the plane for the best views on flights from Seattle to Keflavik. The left seat wins overall because the Mount Rainier and Cascade Range departure view is one of the most spectacular urban-to-mountain transitions in North American aviation, and during the long overwater crossing the left side also faces south toward Greenland's ice sheet as the route arcs over the North Atlantic. The landing view advantage on the right is real but shorter-lived.

During takeoff from Seattle Tacoma International (SEA), sit on the Left side for the best views. SEA primarily departs north on runways 16L/16R (heading ~160°) or south depending on winds. On northbound departures, the left side faces east toward the Cascade Range including Mount Rainier, while the right side looks west over Puget Sound. On southbound departures the geometry reverses, but the dominant departure direction gives the left seat the Cascades view most of the time. Mount Rainier is the unmissable anchor — a 14,411-ft glaciated volcano visible from climb-out. Notable sights include: Mount Rainier (dominant glaciated volcano to the southeast), Lake Washington (large urban lake east of Seattle), the Seattle city skyline and Elliott Bay, Puget Sound islands including Vashon Island.

When landing at Keflavik Nas (KEF), sit on the Right side for the best views. KEF approaches typically come in from the east or southeast over the Reykjanes Peninsula. On final approach heading west or northwest, the right side faces north toward Reykjavik, Faxafloi Bay, and the Snæfellsjökull glacier on the distant peninsula. The left side looks south over the open North Atlantic. The right seat captures the dramatic volcanic lava fields of the Reykjanes Peninsula and the city of Reykjavik across the bay. Notable sights include: Reykjavik city and harbor on Faxafloi Bay, Snæfellsjökull glacier volcano on the distant Snæfellsnes Peninsula, Reykjanes lava fields (dark basaltic terrain directly below), Blue Lagoon geothermal area near the airport.

The flight from Seattle Tacoma International (SEA) to Keflavik Nas (KEF) takes Approximately 8.5 to 9.5 hours.

The great circle route from SEA to KEF tracks northwest over British Columbia and the Canadian Rockies briefly, then arcs over southern Alaska and the Gulf of Alaska, crosses the North Pacific, passes south of Greenland's tip (Cape Farewell), and crosses the Denmark Strait before descending over the North Atlantic toward Iceland. Passengers may see the Greenland ice sheet edge and sea ice in the Denmark Strait on clear days. The route is almost entirely over open ocean for the central 6+ hours with no significant land features visible.