Wouldn't it be great if every time you got on a bus, plane, or train you had an empty seat next to you? No old folks wanting to chat, room to stretch out and take a nap... Well it's easier to keep people away than you think. I present my official guide to warding off Mass Transit commuters:
Method 1: Advocate Something Disgusting
Try bringing a box of inappropriate things to sell onboard or pretending you're a spokesman for something abhorring. If you are loudly trying to sell condoms, I guarantee that people will be viscerally afraid of you. Naturally, things like this won't be possible on a plane as shouting and the like is "not allowed", but planes are almost impossible to get a lone seat on anyway... unless you apply Method 2...
Method 2: Soil Yourself
You really need a lack of dignity and self respect to pull this one off right, but you and I both know the odds of anyone sitting next to a man who rests in a pool of his own pee. On airplanes, this will cause a ruckus, but if you consistently deficate/urinate in your pants again and again no matter how many times the flight staff tries to clean up after you, I guarantee isolated seating sooner or later.
Method 3: Abandon Sanity
There are days when some people want so badly to have a free spot next to them that they are willing to ignore social standards and start speaking to unseen voices around them. One thing is for sure, give it your all. If you sit there and mumble to yourself about trivial things people will snicker and think you to be a harmless schitzo. You have to be willing to sing an entire passenger train car a song about making a sandwich out of your own genitals.
Method 4: Violate the Space Bubbles
Some people are well practiced at ignoring a vocal wierdo, but it takes a strong gut to withstand a stranger who likes to touch you. The way I see it, they violated your space by sitting next to you, so why not violate theirs? Use whatever feels natural. If they aren't incredibly ugly, go ahead and ram your tongue down their throat. Massage people legs. If they're overweight start slapping at their flab. It's most likely they won't ever see you again, so go ahead and make them fear for their lives.
Method 5: Rush Hour
It's really sad when you get on a train, bus, etc and it's already so full of people that you can't sit anywhere. Well, go ahead and help yourself to a seat in someone's lap. I'd give them about two seconds max before they nervously stand up and move to another car. Now that you have their seat, feel free to grin menacingly at the people around you to free up the adjacent seats. If all else fails, and you are cramped in standing room aisles, just extend both your arms to your sides and keep spinning around until you reach your stop.
Keep an eye out for the Transit Authority Police, and good luck.