air travel charge by weight ?

When I fly I am allowed a certain weight allowance for baggage usually around 25 kilos but as I'm thin and weigh less than a sparrows fart why can I not have a larger allowance than the HUGE porky of 25 stone that sits on their seat and my lap ?Or,why can't we all be charged per pound or kilo for our tickets so that skinny folk travel cheeper as they certainly cost less to haul ?
I would point out that this is a LIGHT hearted question and NOT to be taken seriously.
yes sparrows have gas,that fact explains their wavy flight pattern.
feed 1 baked bean to sparrow,put in jar,weigh jar,wait for fart,weigh jar,remove sparrow,weigh jar again =weight of sparrow fart ,easy as !

lol I ask myself the same thing. But. "we are all created equal" So we have to pay the same crap and can't take more.

and while you are at it why not charge by Height- tall people take up more Leg room than short people :)

Same reason they pay the same amount for their seat, even if they have to take two seats...

because thats called profiling and unethical especially from a business's point of view. You want to be charged by how much you weigh? Well I say thank god they dont do that because for 1 it would be REALLY expensive and 2 there would be no airlines because it would drive them to bankruptcy. use some common sense.

Just exactly how much does a sparrow's fart weigh?
And how would you find out, I wonder?
Do they even have gas? Hmmmm.
:-)

Edit: Ah - now I am enlightened, Mallory. Thanks.