Best place is still the lavatory. The huge "sucking" effect of the toilet will suck out the fart as well.

I read an article sometime ago, and it's based on a true story.
A woman farted on the plane in US. An in order to aviod the smell and the embarrassment, she lit up a match in the cabin, thus setting the fire alarm. The plane was then diverted and landed immediately. So seems like it even got more embarrassing afterall?