Little laughs during this 'Date'

“Due Date”

One and 1/2 stars

By Thomas Tracy

Though “Due Date” is essentially a fusion of “Planes, Trains and Automobiles” and “Tommyboy,” both fairly entertaining films of the road trip genre, its laughs are few.

That’s because the flick often misses the tone set by those who had already mapped out this comedy vein, especially when odd couple Robert Downey Jr. (“Iron Man”) and Zach Galifianakis (“The Hangover”) are thrown into situations that are more painful than laugh out loud funny.

Following the rules of the road trip comedy to the letter, the four screenwriters (count em’ — four!) behind this hum drum dramedy make sure that Downey’s dour Peter Highman can’t stand Galifianakis’s Ethan Tremblay when the imbecilic pot smoker causes a stir at the airport and gets them both put on a no-fly list.

But Peter has to hit the road, and fast — his wife is about to give birth to their first child in L.A. 

Kicked from his flight without his wallet — which makes absolutely no sense since an Air Marshal would probably want to see the ID of the person he’s pulled off a plane — Peter can’t rent a car or buy a bus ticket, so he grudgingly accepts a ride with Ethan, his self-pleasuring bulldog and the ashes of his late father.

The rest of the movie is predictable — the two go through a series of hare-brained adventures as they travel through the Southwest. But instead of evoking belly laughs, these asphalt pratfalls bring forth only a few chuckles at best.

But it’s not for a lack of trying: Downey tries to make his stuffy straight man more interesting by throwing in a few deep-seeded anger issues that often get him in trouble.

Galifianakis tries to make his character adoringly stupid, but after about an hour, you really just begin to wonder if Ethan is mentally ill.

Supporting actors Julliette Lewis (“Whip It”) and Jamie Foxx (“Ray”) try to kick the idling film into high gear, but they’re not in it long enough to make a lasting impact on the long, unimpressive road ahead.

“Due Date.” Starring Robert Downey Jr. and Zack Galifianakis. Directed by Todd Phillips. Running time: 100 minutes. Rated R for language, drug use and sexual content. Playing in Brooklyn at Access Digital Theatres - Pavilion Cinema in Park Slope, Cobble Hill Cinemas, UA Court Street Stadium 12 in Downtown, Kent Theatre in Coney Island, UA Sheepshead Bay 14, Bay Ridge Alpine Cinemas, and Linden Boulevard Multiplex Cinemas in East New York.