The looks on the female flight attendant's faces when their camp male coworker finally sees his girlfriend and they start enthusiastically making out.
The guy who gets bitten by a snake by Groin Attack. And the snakes turning out to be equal opportunists when a girl gets bitten as a Breast Attack.
"Get off my dick!"
When the couple are getting attacked by snakes in the lavatory, two of the flight attendants assume all the banging around and screaming are sex noises. The woman attendant claims, "Oh he is GOOD." The screaming abruptly stops, and she changes her tune: "Well, maybe not that good."
The Martial Artist's Moment of Awesome, wherein he manages to rush into the cabin full of snakes to piggyback a young woman out quickly becomes this when, halfway to safety no less, she demands they go back for her chihuahua. He does so.
Speaking of the martial artist, when he's introduced in the film, the camp flight attendant starts a conversation with him, claiming he's a martial artist too. He does one kick as a demonstration and pulls a leg muscle.
"It's a teal, Doc!"
Mercedes snapping, "Ever heard of email, dickward?" at the annoying businessman.
Samuel L. Jackson's tongue in cheek speech about the film's inevitable victory for best movie the following year.
Samuel L Jackson: I'm here tonight to present the award everyone's been waiting for: best movie. This award holds a special place in my heart because next year I'll be winning it for Snakes on a Plane. Now I know, I know that sounds cocky, but I don't give a damn. I'm guaranteeing that Snakes on a Plane will win best movie next year. Does not matter what else is coming out. New James Bond... no snakes in that! Ocean's 13... where my snakes at? Shrek the Third... green, but not a snake. No movie shall triumph over Snakes on a Plane. Unless I happen to feel like making a movie called Mo' Motha-fuckin' Snakes on Mo' Motha-fuckin' Planes.
When one of Neville's coworkers theorizes that the snakes are on some kinda drug hence their crazed rampages, he summarizes it as thus:
Three G's: (to Troy) You like that? Baby got back, front and side-to-side. Hey, y'all two get together, y'all might have, like, two 20-lb babies or something. Troy: (briefly laughs to humor Three G's, but abruptly stops when he faces forward again, looking annoyed)
When Rick, who had been knocked unconscious and bitten by a snake on one arm, crawls out of the control chamber and gets back in the co-pilot seat, Claire wonders if he's in condition to fly with only one hand. Rick gives a retort that's both eye-rolling and hilarious: "Honey, you'd be surprised what a man can do with one hand."
Early in the film, Neville calls Harris, his FBI buddy:
Neville: Harris, so how's the new promotion? Harris: I'm loving it. Neville: That was a little quick. Wanna try again? Harris: No no, I'm serious, man. You know, no more, no more junk food hangovers after all-night stakeouts, you know? I'm actually spending nights in bed with my wife. She's hot. You know, and my kids, you know, forget about 'em. They're kids. I'm just spending every waking minute with them. You know, they're fun. Neville: Please, this is me you're talking to. You know you miss it. You miss the action. You're bored to tears. So what are you actually doing with your time? Harris: Surfing the net. Neville: Porn, no doubt. Harris: No, hey, eBay, my cynical-minded friend. I'm right in the middle of a bidding war with this punk-ass kid from Iowa for this black velvet Pamela Anderson poster. Not technically porn.
A young boy is bitten in the arm by a snake. A foreign woman knows how to buy him more time: She cuts open his bite inflammation, then transfers olive oil into the open wound via her mouth. Troy pipes up: "Uh... I got bit too."
Even funnier once you find out that the leis were specifically sprayed with pheromones to attract and rile up the snakes. That snake wasn't wrestling with the lei, it was attempting - very persistently - to mate with it.
A passenger who's afraid of flying tells his new wife, "Look around the plane. How come there aren't more people on this flight? I can't figure it out." His wife replies, "Honey, 'cause it's the red eye."
The famous line "I've had enough of these motherfuckin' snakes on this motherfuckin' plan" is hilarious enough for sheer absurdity, but then you hear the bowdlerized version used for cable airings:
"I've had enough of these monkey fighting snakes on this monkey fighting plane!"