The **** is wrong with some of you people?   
 
The War Machine issue is a legitimate question.   There's several reasons that both fanboys and non-fanboys alike will be wondering where WM/Don Cheadle is in the film:
 
a) Rhodey is Tony Stark's right hand man.   Even after he suited up as War Machine in IM2 and they traded licks, in the end, he comes back around and stands back to back with his bro and lays the smack down on Whiplash and an army of drones.   
 
b) Pepper Potts is in it.   You don't have to be a fanboy to ask why the hell Gwyneth gets a cameo, and Cheadle doesn't. 
 
c) Earth is under attack, and Fury is putting together Earth's Mightiest Heroes to defend the planet.   There is no conceivable reason whatsoever that Fury and SHIELD would not have considered War Machine a top prospect for just such an initiative.   
 
d)  War Machine is an Avenger.  Some of you who posted that he *isn't* have never read an Avengers comic in your life.   War Machine IS AN AVENGER.  Mainline to a lesser extent, but he sure as hell was a MAJOR player in West Coast Avengers and Force Works.  Hell, War Machine has a bigger claim to be a canonical Avenger than Hulk ever did.   
 
e) And face it:   War Machine is black.   Yeah, so is Fury, but he's the leader and mentor in the film, an operational and logistics guy, rather than a front-line glory boy like the "true" Avengers.   It sure as hell wouldn't hurt at the box office to include a "hero of color" or two just to reach out to audiences who might otherwise dismiss this movie as being just another comic book film targeted at white geeks.   If nothing else, it's a missed opportunity for a broader demographic, and that's kinda surprising for Marvel when Feige's aim has been to reach 
beyond just the loyalists who dutifully watched all the prequel movies.   
 
 
People can extrapolate and come up with all kinds of reasons War Machine wasn't on the front line in this movie, and you might even come up with some good ideas.    But Joss apparently didn't bother, or else whatever mention he made of it wound up on the cutting room floor.   And however slight or major you choose to make of it, it's still a disservice to comic book fans, to fans of the Iron Man movies, and definitely to Cheadle himself.
 
And on a personal note, I just want to say that I'm actually disgusted by the way a lot of you treated J Howlett on this issue and tried to act like he was "bat-trolling" for daring to bring up a legitimate question that he was genuinely concerned about.   I've definitely seen my share of Nolanite "trolling" on this forum and many others, but the way you guys treated J Howlett makes you no better than the "Nolanite hordes" you always have fun bashing.   The maturity level on these threads is usually a lot higher than this from you guys.   Don't know why some of you felt compelled to lower your standards in here today.   
 
/rant.