Sometimes the best vacation sightseeing begins before the wheels touch down on the runway.

A number of regularly traveled commercial flight paths showcase some of the nation's most beautiful vistas, from the Grand Canyon to Alaskan glaciers to historic lighthouses en route to Portland, Maine.

Pilots have their favorites views, and some tell stories of days before high fuel prices when they would seek permission from air-traffic controllers to pass close by prime sites or even double back to give passengers on both sides of a plane a great view.

A "canyon tour" of the Grand Canyon used to be a popular request to air-traffic controllers—pilots would descend to 5,000 to 10,000 feet above the canyon and fly over the top of the Colorado River for spectacular views while approaching Las Vegas.

Some pilots still request permission for a procedure known informally as the "Bay Tour" on southbound flights leaving San Francisco. Controllers instruct pilots to level off at 2,000 or 3,000 feet above sea level as they follow the bay out to sea, flying over the Bay Bridge, past Alcatraz and then over the Golden Gate Bridge. At the Golden Gate, flights turn to a southwesterly compass heading and climb to 10,000 feet to continue to Southern California.