“Toward A Social Psychology Of Flatulence”

That's the name of a study exhumed from a 1980 edition of Psychology: a Quarterly Journal of Human Behavior:

How did it turn out? Well, it turns out people will rank you politely if your fart is silent and odorless (probably because they couldn't tell), but politeness ratings go down somewhat for the silent and deadly, and take a sharper dive when the fart is LOUD. Sound matters more than smell in terms of politeness, apparently.

However, while people may not think you're polite, they WILL think your loud farts are funny, with people who fart loudly being ranked as more humorous (though women did not find it as funny as men). If they know you did it deliberately, however, they are more likely they rank you as "malicious", ESPECIALLY if the fart is rank (silent and odorless apparently means you're a relatively good person here).

The sex differences were a little surprising. It turns out that women are more forgiving of loud, accidental farts (girls, we've all been there I'm sure), and don't ding the farter so much on "politeness".

Man, on the plane back from Los Angeles, the dude next to me (or someone close) was releasing silent killers for a full hour. I think I prefer the loud ones. Laughter helps alleviate the pong. Being slowly enveloped by someone else's gas, and being immobile, well … that's marriage, not air travel.