Sit on the Left side of the plane for the best views on flights from Ontario to Seattle. Left side wins both ends of the flight. During the cruise northward through California and Oregon, the left side also tracks closer to the Sierra Nevada and Cascades including Mount Shasta and Mount Jefferson, making it the stronger choice for the entire journey.

During takeoff from Ontario International (ONT), sit on the Left side for the best views. Ontario typically departs westbound on runway 26L/26R, then turns northward. The left side gives you a clear look back at the San Gabriel Mountains rising sharply to the north, with the sprawling Inland Empire grid below. You'll also catch the eastern edge of the Los Angeles Basin spreading out toward the coast. Notable sights include: San Gabriel Mountains, Inland Empire urban grid, San Bernardino Valley, Mount San Antonio (Mt. Baldy).

When landing at Seattle Tacoma International (SEA), sit on the Left side for the best views. SeaTac predominantly lands on runways 16L/16R heading south, meaning the approach comes from the north over Puget Sound. The left side faces east, giving you a prolonged view of Mount Rainier dominating the horizon, the Cascade Range stretching north and south, and the city of Seattle with Elliott Bay just before touchdown. Notable sights include: Mount Rainier, Cascade Range, Elliott Bay and Seattle skyline, Puget Sound.

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

Central Valley of California, Sierra Nevada foothills transitioning to the Cascades, Mount Shasta (visible as a massive isolated volcanic cone near the California-Oregon border), Crater Lake region in southern Oregon, Oregon Cascades including Mount Jefferson and the Three Sisters, Willamette Valley before crossing into Washington state