Yes, Soul Plane is no Kurosawa or de Sica stuff, but it's funny.
Yes, it contains vulgarity, nauseating scenes, foul-mouthing, insults, indiscriminate use of the omnipresent "N-word" and "Motherf---ers", racial stereotyping and what-have-you, but everything in it is so absurd that it becomes funny. Actually absurdity is, in my opinion,the strongest point of this movie; it's so extreme in its incredulity that not for a single moment does it let one feel that this movie, even in one's wildest dream (with or without any assistance from pot), could have the slightest similarity to reality! Thus, all one needs to do to enjoy this movie is to switch off all logical reasoning and just watch it for the fun of it.
Though I am not an African-American person (and thus, I can not comment on the humiliation felt by some African-American reviewers), I can see that this is not a racist movie; rather, it pokes fun at many of the prevailing stereotypes, though definitely not in a polished way.
Come on! If a movie like this can make one believe that all blacks are busy smoking pots and whoring, then one must be having the brain of a caterpillar. I'm sure, most people know about renowned personalities such as Langston Hughes, Tony Morrison and Condoleezza Rice (to name just a few)and their contributions in their respective field of choice.
Actually, I found it more offending to see Jammie Foxx using "motherf---er" in "Collateral" (because it did not fit his decent disposition, and that, to me, was surely Hollywood stereotyping, where every black actor must foul mouth!) than Muggsy using the N-word here. I also found it equally funny, when Marsellus Wallace asks Butch:"Are you my ni---r?" in "Pulp Fiction", but not when, Harvey Keital used the N-word in "Reservoir Dogs". But then, that's me!