On a recent long-haul flight to London, I spent time trying to find something to watch on the onboard television. Among the new movie selections were “Captain Marvel,” “Creed II” and “Aquaman.” The two superhero movies and the sequel to the reboot of the “Rocky” series are emblematic of our age of unoriginal content and comic-book pastiche superheroes passed off as adult entertainment.

This sense of cultural exhaustion and unoriginality is part of the broader trend that inhibits Americans’ ability to confront problems at home and abroad. When a culture stops producing original content and supplants it with recycled kitsch, it inevitably is sending a message of decline to other societies — and future generations.

Mass media reflect culture and the ideas of a generation, the way the Hollywood golden ages mirrored America’s moment of cultural confidence during the interwar and postwar years. Today’s biggest blockbusters are a contagion of nonstop action and one-dimensional characters catering to short attention spans.

Hollywood — once so innovative with the original “Star Wars” in 1977 or “Alien” in 1979 — hasn’t had a big new idea for years. This represents a historic decline in American originality and pessimism about the US role in the world. A similar funk can be felt in the halls of academia and at the political ­podium.

Why are we being asked to rewatch a “new” “Lion King” and “Aladdin”? Why are we having to suffer through yet another “Spiderman,” “Men in Black” or “Godzilla”? Compare these to the top films of the 1970s, such as “The Godfather” or “Jaws.” Or recall controversial but sharp flicks like “The Graduate” or the thoughtfulness on display in “Guess Who’s Coming to Dinner” in the 1960s.

The 1990s at least brought us the original “Aladdin” and “Lion King” and epics such as “Titanic” and “Saving Private Ryan.” There is more character development in 20 minutes of dialogue in almost any major film produced between 1960 and 1990 than in the entire two hours of more recent major films. Think: “Southern Comfort” (1981) vs. the 17th “Spiderman” remake.

The decline therefore is not just in content and character, but particularly in originality. It is shockingly vacuous. Recent Democratic debates mirror this problem, providing comic-book mythological solutions, like “reparations,” coupled with promises to use diplomacy to confront all the world’s ills, a naivete in a world where America’s adversaries use strength and military power.

The recent obsession with comic-book superheroes is a way to mask the need for cathartic discussion about complex problems facing the United States, such as economic challenges eroding the middle class. There’s also a tendency to tear down controversial history rather than add more nuance to it and address an America perhaps more divided than ever since the Civil War.

Is the problem that there is a vacuum of ideas in American culture, the long-term affect of what Allan Bloom called the closing of the American mind in 1987? Or is it that we are being fed the notion that magical solutions, such as the socialism-cure-all that Bernie Sanders has preached, can fix society? It may be that we are being led into a false sense of all will be well when we know it won’t.

The 1950s era of film and mass media was similar, offering up “Peter Pan,” “Cinderella” and “The Ten Commandments” that ill-prepared viewers for the difficulties ahead in the 1960s. To the credit of the generation of the 1960s, they embraced these challenges through protest and experimentation, not retreating to read comics.

It is essential to step back from consuming action-packed noise in place of reality. From social media to books and music, the trends are in the wrong direction. We are searching for nostalgia to fill our minds, but this nostalgia for ­rebooting old movies and characters generally leaves us with a less interesting copy each time it is ­reenacted.

If America wants to do more than just reproduce a faded copy of itself in the 21st century, it has to stop relying on recreating the 20th century’s blockbusters and ask of this generation to fill the vacuum of ideas with robust answers of its own.

Seth Frantzman is the op-ed editor of The Jerusalem Post. Twitter: @SFrantzman