Call it the Queen of the Skies Retirement Tour 2017.

With United Continental Holdings Inc. joining rival Delta Air Lines Inc. in retiring the iconic jumbo jet this year, plenty of aviation enthusiasts may be pondering a trip or two to experience a U.S.-operated 747 one last time .

Chicago-based United first flew the 747 in 1970, the same year that Pan Am began service as the long-haul behemoth’s launch customer. An aerial ambassador of American wealth, power, and global commercial dominance, the plane quickly became a cultural icon—especially after it became Air Force One.

“It’s a bittersweet milestone—this jumbo jet with its unmistakable silhouette once represented the state-of-the-art in air travel,” United said in a statement. “Today, there are more fuel-efficient, cost-effective and reliable widebody aircraft that provide an updated inflight experience for our customers traveling on long-haul flights.”

For now, United uses the airplane mainly for trans-Pacific routes. Most of its 20 747s are based at its San Francisco hub, where they serve Beijing, Hong Kong, Shanghai, Seoul, Taipei, and Tokyo. It also flies the 747 between San Francisco and Frankfurt. For summer, when leisure travel increases, it plans to use the jet for one of two daily San Francisco-London nonstops. But United says the 747 garners the lowest passenger scores in its fleet. This year, the carrier said, will be the last for the four-engine plane with the bulging fuselage.

Delta meanwhile is rapidly winding down service with the last of its five 747s, which are deployed from its Detroit hub to Seoul, Shanghai, and Tokyo. When its fleet was larger, Atlanta-based Delta flew the plane from Detroit to Beijing, and from New York to Tel Aviv and Tokyo.

Neither airline has disclosed when exactly its final 747 flight will be. Delta has loaded 747 schedules through late November; United said its last 747 flight would occur in the fourth quarter. But the end is near.

©2017 Bloomberg L.P.

This article was written by Justin Bachman from Bloomberg and was legally licensed through the NewsCred publisher network.

Photo Credit: Airlines in the U.S. will retire their 747s, like this one operated by United, this year. United