The formula for the success of a spoof movie is very particular. You need to go after a movie that people will recognize. Airport was a blockbuster, so people got what Airplane! was trying to do. You need to go after a movie that takes itself seriously. Nobody could successfully spoof Animal House because the spoof wouldn't be funnier than the original. You need to be poignant with your jokes. The ____ Movie films fail because they just throw loads of crap against the wall and see if any of it sticks (99.9% of it doesn't). Delta Farce fails on the latter two of these accounts, but it most egregiously misses on the second count. Delta Farce spoofs a spoof. Bad idea.
See if this plot rings a bell. Three goofy, but well-intentioned, men end up in Mexico. After fighting poorly, but winning by surprise, some locals ask the men if they will help protect a small village from outlaws. The men try, fail, but somehow muster the courage, with the help of the noble townspeople, to defeat the bad guys. If those three men are played by Steve Martin, Martin Short, and Chevy Chase, you're talking about The Three Amigos. That film was a spoof of The Magnificent Seven, and I probably appreciate it more through nostalgia than the film's actual quality. If those three men are played by Larry the Cable Guy, Bill Engvall, and a mustachioed DJ Qualls? Uh-oh.
The three actors (Qualls replaced Jeff Foxworthy, who couldn't make it because of scheduling conflicts) play National Guardsmen, who are called up to fight in Iraq. They are ill-prepared, but they joined up and they have to carry out their duties. Thanks to circumstances that make so little sense that I won't recount them, the men end up dumped in the middle of Mexico. Of course, they think they're in Iraq. The fact that people ARE SPEAKING SPANISH TO THEM doesn't change their minds. I think I can understand ignorance, maybe even racism. But confusing Arabic and Spanish? The men don't realize they aren't in Iraq, until one of the villagers tells Larry -- and he doesn't have a last name in the movie, so his uniform says "Larry" on it -- at which point he realizes that one of his other men is wearing a sombrero and he notices the pinatas everywhere.
Because one of the villagers is hot, the men decide to stay and fight. They drink and dance. The bad guy is played by the great Danny Trejo, and even he is horrible in this movie because the writing is so bad. The three main characters? Nobody ever confused Larry the Cable Guy with Chevy Chase as an actor, much less Steve Martin. A few hundred racist and homophobic jokes later and the men find a way to win, of course.
There is no denying the poignancy of the plot, no matter how off the jokes may be. Mexico is a very violent place right now and the people are terrorized. Everyone who tries to help seems to be getting murdered. Judging by their success in protecting the village, perhaps we should send Larry the Cable Guy and company to Mexico to bring peace. Whichever way it comes out, it's win-win.