In a very similar vein to your horse joke, are you familiar with the guy with a giant orange head? That one is funny precisely because it gets dragged out so long and ends with a straight answer. It’s also funny because it seems like almost every other joke you’ve ever heard so you are REALLY expecting a stereotypical joke twist ending. It’s my favorite joke of all time 
The OP’s joke is my all-time favorite, although instead of an airplane, I use a duck. Ducks are inherently funny.
My second favorite non-joke:
Q: Why are elephants big, grey, and wrinkled?
A: Because if they were small, white, and smooth, they’d be aspirin.
Tell it! Tell it!
Along these lines is the venerable brick joke. I love it, but I’ve only had the courage to tell it a couple of times. But while I was searching for that just now, I also found this shorter, funnier version. Puttin’ that in my pocket.
I laughed out loud. Found it definitely funny.
I think the airplane one is pretty funny, but it can lose something if not delivered right.
One of my favorites is the “Fuck you, clown!” shaggy dog story. I’m not the world’s greatest joke teller, but when you hear from someone who knows what they’re doing, it can be pretty fun, a la the Aristocrats, but not as dirty. The version I’ve heard usually involves an extra incident or two with the clown, being embarrassed in front of his girlfriend, vowing revenge, studying to come up with the perfect retort, etc…That link is just a skeleton for the joke. You can fill in whatever you want, and it’s fun to see a good improviser run with it.
So an old friend of mine called me up the other day and told me he had the most incredible story to tell me, so after we chatted for a bit I jotted down his address and agreed to meet him.
At first I thought I had written it down wrong because I was in a really fancy neighborhood, I’m talking like $10 million dollar homes here. This friend of mine, well he wasn’t loaded when I knew him, so I figured if I was in the right place, he must have won the lottery or something because there was no way he got this rich any other way.
So I find his gated estate and they buzz me in after I tell them who I am and who I’m there to see. At this point, I can’t believe it but I guess I really am at the right place!
So I make my way up the long driveway, someone meets me and takes my car and goes and parks it somewhere. I walk up to the door and ring the bell. It takes a few minutes but finally it opens and the most beautiful woman I’ve ever seen in my life greets me.
After I pick my jaw up off the floor the woman introduces herself as my friend’s wife. I’m amazed. I mean, my friend is a nice guy and all but he was hardly a looker in any sense of the word. There’s just no WAY this woman could be his wife. I still was doubting I even had the right place. But she smiled and hugged me and waved me inside and told me that my friend was really excited to see me and she pointed back to where I could meet him.
So I’m making my way to the back of the house, in utter and complete awe at just how freaking ritzy it is. I mean, I’m talking huge marble statues, gold-leaf decorating everywhere, huge vaulted ceilings and spiral staircases. I’d never seen or imagined anything so fancy in my entire life. So I’m just kind of futzing my way further and further into the house, when suddenly a voice calls out to me, “Drew! There you are!!! It’s so good to see you!”
I recognize his voice instantly, it’s my old friend! But… when I look over at him, well… something’s wrong. You… you’re never going to believe this but, well my friend’s head… it was giant and COMPLETELY orange! I had to do a double… no a triple take to confirm what I was seeing. But sure enough, it was him… it was my old friend, several years older than when I had last seen him, with a giant orange head.
So he waves me over and shakes my hand and is all smiles. Meanwhile I’m just thinking I’m in some sort of a dream… or a nightmare or something.
So… well I figure he has some sort of a medical condition I’ve never heard of, and I’m trying to be really polite by not bringing it up. I don’t want to be rude or anything. So we’re chatting about the good old days and what not, but he keeps noticing how I’m just looking at his head, my eyes furtively glancing around it from top to bottom. Eventually he speaks up, “So, you wanna know what happened to me, don’t you? It’s ok… I’ve been racking my brain about it all and I think it’d be good to talk to someone.”
So I nod and politely agree to hear his story. “Well you’re never going to believe it but a week or two ago I was walking along the beach and I found an old oil lamp. On a lark I gave it a rub, and what do you know, a genie popped out and granted me three wishes!”
I kinda just roll my eyes at him and then he goes on, “No seriously. So the first thing I wish for is to be a multi-millionaire. He nods, folds his arms, and before I know it, I’m surrounded by a giant mansion, a wallet full of hundred dollar bills and a dozen limitless credit cards, and a bank account with millions.”
I kind of give a nervous laughter of agreement, but I’m thinking my friend is entirely off his rocker and this is some sort of practical joke. “So the next thing I wish for is to be married to the most beautiful woman in the world, naturally. In the next moment, there she was, standing beside me, and matching rings were on our fingers. She pulls me in for an embrace and a kiss and tells me that I’m the most important thing that ever happened to her and that she loves me more than anything else in the world.”
“Well naturally, the genie asks me what my 3rd wish is. Now you know, I think this is where Imay have gone wrong. I wished for a big orange head.”
Oh my god, I’m dying! Even after you told me what the joke was going to be.
Killer, man.
My favorite knock-knock joke.
This is a good observation, but I think even one joke can set the mood for the deadpan, literal reply to work.
When I was in high school, I was driving along and saw a friend of mine walking; I pulled over and asked if he needed a ride. He did, so in a fit of what passed for humor in my younger days, I said, “Well, like the man said to the one-legged hitchhiker: hop in!”
He looked at me gravely, got in, and replied, “Like the one-legged hitchhiker said to the man: thanks!”
It was the perfect, grave, serious delivery that cracked me up.
I remember one from when I was kid:
Q: What did the the frying pan say to the stove?
A: Nothing, Frying pans can’t talk.
I laughed at the OP’s joke, and at most of the others in the thread. The horse and big orange head jokes were new ones on me, but really funny.
The “fuck you, clown!” joke is one of my favorites, and I tend to say the punchline any time I want badly to have a witty reply and can’t think of one.
[spoiler]What’s red and smells like blue paint?
Red paint.[/spoiler]
I laughed at the airplane joke.
CMYK’s link gave me this one, which I think may actually be the ultimate SDMB joke:
Knock knock.
Who’s there?
To.
To who?
To whom
My favorite knock-knock joke:
Knock, knock.
Who’s there?
Nobody.
Nobody who?
I heard the OP’s joke years ago in high school, although it used “orange” instead of “airplane”. I think “orange” (or “duck”, as mentioned above) is just inherently funnier than “airplane”.
The particular situation made it funnier than just reading it on a message board. We were all hanging out in the student common area during lunch telling jokes, and someone told the “Ask me if I’m an orange” joke. IIRC, some people thought it was kinda funny and others didn’t. But as other kids came into the room, they would be asked the “orange joke” too – “Hey Dave, ask me if I’m an orange!” It got funnier each time as everyone was anticipating the reaction of the new target. Finally a teacher walked by – “Hey Mrs. K, ask me if I’m an orange!” – and the “No” punchline got a HUGE laugh from everyone except the teacher, who just sort of went “Okay” and continued on.
There were a few variations in how the “No” would be delivered, e.g. deadpan, surprised, offended, upbeat, but I think deadpan is funniest.
Incidentally, one of the most famous jokes in the English language has this same “the twist is that there is no twist” structure:
Q: Why did the chicken cross the road?
A: To get to the other side!
Another one I remember from childhood is:
Q: Why do firemen wear red suspenders?
A: To keep their trousers up.
I love the big orange head one. One of the characteristics of anti-humor is that it can be used to torture the audience with length, but it’s not necessary – when my dad told me that joke recently, it was a lot shorter. You just have to set up the expectation in your audience that they’re about to envoy Ted a humorous twist of expectations, and then pay it off by having the humorous twist be that there’s no twist at all.
–Cliffy
Back during the summer, I (genuinely) had a meta-joke encounter with a neighbor in my bungalow colony. She knocked on the door and, while physically knocking, yelled “Knock knock!”
So I responded, “Who’s there?”
She answered, “Naomi.”
I asked, “Naomi Who?”
Puzzled (and humor-impaired) she said, “Naomi Sandel.”
I responded, “That’s not much of a punchline.”
She then said, “I just stopped by to ask how do I get to Camp Mogen Av.”
I answered, “Practice, Naomi, practice! Now that’s a proper punchline!”
In the same vein:
Two muffins are in a muffin tin, baking in an oven. One muffin turns to the other and says, “Phew! Hot in here, isn’t it?” The other muffin says, “HOLY CRAP, A TALKING MUFFIN!!”