In the past decade or so, I’ve noticed an increase in films that shout strongly to previous tales that inspired it. Whether someone is rewriting “Pocahontas” and calling it “Avatar,” or “Dr. Jekyll and Mr. Hyde” and calling it “The Nutty Professor,” there are way too many similarities to ignore the fact that the writer had the corresponding movies in mind while creating the script.

There’s one thing that kept screaming out to me as I watched “Due Date,” and that was John Hughes’ “Planes, Trains, and Automobiles.” In “Planes,” the stressed-out businessman (Steve Martin) and the obnoxious travelling salesman (John Candy) must travel cross-country for Thanksgiving, and mayhem ensues.

“Due Date” is a cross-country comedy of circumstances getting worse before they get better. Peter (the always fantastic Downey Jr.) is an egotistical, Bluetooth-savvy, stressed out businessman flying home for the birth of his first child. After being kicked off the plane because of wannabe actor Ethan (Zach Galifianakis), Peter finds himself on the no-fly list, leaving him no choice but to travel by car 2,000 miles with his newfound friend Ethan.

For what it’s worth, the duo really hit it off. Downey especially hits the nail on the head. He’s a natural for comedic acting and indulges the audience into the fast-talking asshole we all love to watch.

Galifianakis is as funny and obnoxious as he was in “The Hangover.” Sadly, that’s all he is; the weird, off-the-wall bearded potbelly who doesn’t seem all-there with it, screwing up every situation. We’ve all seen it before, only this time he has a dog.

Nonetheless, the couple adds something compelling and more powerful to the story that isn’t shown often enough: soul. It’s hard to make the transition between “I despise you on a cellular level” and “I want to kiss you,” but they do it perfectly. The pair injects real soul into creating the “needing each other” concept with an improv exercise in a gas station bathroom, where Galifianakis lets out his true sweat and tears.

Unfortunately, strong acting talent isn’t enough to call “Due Date” a stand-out comedy like “The Hangover.”  Bottom line: it’s too long. Surely it has its share of hilarious moments, followed by useless dialogue and a montage of a car and American scenery. The film would be completely strenuous for someone with ADD. The pace is way too slow between jokes. And it doesn’t help that this film goes over the top, with such scenes as a jailbreak/car chase scene that had me sighing until it was over. The filmmakers seemed like they were trying too hard.

In addition,  Jamie Foxx is in the film for 10 minutes (which seems more than enough) as Downey’s best friend, introducing us to some suspicion of who the real father of the coming child might be. In brief, it really doesn’t pertain to anything, and I just didn’t care. This, however, does not stop Todd Phillips from bringing in an onslaught of big-name celebrities for other random parts, such as Juliette Lewis, Matt Walsh and Danny McBride. McBride who absolutely steals the scene as a Western Union employee who won’t give Downey his money; it’s a side-splitting sight to behold.

Whether it’s the battering of children or smoking pot at the U.S.-Mexican border, the movie has its laughs. Unfortunately, “Due Date” is carrying a 300 pound gorilla on its back called “The Hangover,” and falls short of its expectations.