Last time I brought fast food on board I realized as soon as I sat down how strongly it smelled--and it was just a grilled chicken sandwich from BK. I wolfed it down pretty quickly to try to avoid offending others' nostrils, but even then the odor lingered. I actually felt kinda bad about it, and will definitely try to gobble up my sandwich before boarding next time.
I was going to say something about this being the inevitable outcome of airline cutbacks in in-flight food. But then it occurred to me that the turkey pastrami sandwiches from Uncle Gordo's Turkey Farm can be pretty odiferous--to say nothing of UA's garlic-and-flour snack mix (which I could still taste even after brushing my teeth twice--and I like garlic!).
Then there were the AA domestic veggie meals of the late 90's. I once had falafel that smelled of garlic something else. It was pretty tasty (quite a pleasant surprise, actually), but I felt bad for the guy sitting next to me, who had to smell the sandwich (and then me) for the rest of the flight. Poor guy.
Now if they could just find a way to harness the fast-food-fed pax's gaseous output to the fuel tanks, the airlines could probably save quite a bit on fuel costs! Can jet engines run on methane?