Two movie classics celebrate big birthdays this week. “Back to the Future” turns 25 and “Airplane!” turns 30. Both helped to define their eras and stood the test of time as enduring favorites.

One of my favorite critics, Ali Arikan, has a superb tribute to “Back to the Future.”

Marty McFly has more in common with George Bailey than the film’s slightly cynical conclusion suggests. His adventure in the ’50s is literally based on self-preservation, but this is only derivative of his true goal. Recall the aforementioned scene at the dinner table, as Marty looks longingly, sadly, but lovingly at his parents, wondering where it all went wrong. The same look adorns his face just before he says goodbye to Doc, and the frequent times he runs into the younger selves of the townsfolk. Ostensibly selfish, his quest is, nonetheless, for the good of the community: personal success is just a welcome by-product. Back to the Future has a joyously optimistic view of the human race: it believes that, given the means, we would stand up to the physical laws that govern the universe (which Carl Sagan famously called “god”) just to make our loved ones happy. No wonder the film’s signature tune is called The Power of Love.

Hard to believe, but we’re only five years away from the time Marty McFly visits in part 2, the one with the flying skateboards.

“Airplane!” was in some ways a throwback to some of the wilder comedy of the vaudeville era like “Hellzapoppin'” and its joke-a-minute structure was in part influenced by the television show “Rowen and Martin’s Laugh-In.” Coming just ten years after the Oscar-winning “Airport,” it seemed a brash, subversive, iconoclastic upending of just about everything ever taken seriously. It was a surprise success. Made for just $3.5 million, it earned 83 million in North America alone and is 10th on the American Film Institute’s list of the funniest movies of all time.