Sit on the Right side of the plane for the best views on flights from Barcelona to St. Louis. While Barcelona's departure offers immediate coastal drama, the landing at St. Louis provides superior scenic variety and landmark density. The Mississippi River system, river confluence, Gateway Arch, and bluff terrain create more visual interest than the relatively flat Midwest cruise segment. The right side captures both a dramatic approach and the geological/urban features that define the St. Louis region, scoring higher overall despite the left side's strong takeoff.

During takeoff from Barcelona (BCN), sit on the Left side for the best views. Barcelona's Mediterranean coastline and harbor are visible during climb-out on the left side. The city skyline, Montjuïc hill, and the curve of the coast toward the Balearic Sea provide immediate visual interest during departure. Notable sights include: Barcelona harbor and breakwaters, Montjuïc hill, Mediterranean coastline curving south, Collserola mountain range inland.

When landing at Lambert St Louis International (STL), sit on the Right side for the best views. The approach to St. Louis from the east crosses the Mississippi River valley with the river itself visible as a major landmark, plus the confluence with the Missouri River. The Gateway Arch and downtown St. Louis skyline are visible during final descent, and the surrounding bluffs and floodplain provide terrain variety absent on the left side. Notable sights include: Mississippi River and its meanders, Missouri River confluence, Gateway Arch and downtown St. Louis, river bluffs and floodplain.

The flight from Barcelona (BCN) to Lambert St Louis International (STL) takes 9h 15m.

The flight crosses the Atlantic Ocean (5+ hours of open water with minimal visual interest), then enters North American airspace over Newfoundland and the Canadian Maritimes. The cruise segment over the Atlantic dominates the middle portion of the flight. Upon reaching the continent, the route passes over the Appalachian Mountains (visible as a ridge system in the eastern United States), then crosses the Ohio River valley and enters the Mississippi River basin. The Great Plains of the Midwest appear relatively flat with scattered cloud cover typical of the region. No major mountain ranges or dramatic terrain features are visible during the long transatlantic cruise.