Can anybody provide any real evidence that nut allergies are triggered by the "smell" of nuts? I don't think so -- as far as I know they have to be aerosolized in a cooking spray or finely crushed and thrown into the air as "nut dust". I'm betting this woman is probably just a hypochondriac who thinks she's being affected by smelling nuts when she's not. This article http://www.nationalpost.com/related/topics/story.html?id=2417934 mentions that her claim is backed up a doctor's note saying that she has a reaction when in the general vicinity of nuts, but other than that there's no real evidence for this.
Air Canada and other organizations should first order complete medical studies on people like this to get the facts before taking action. Clearly, the public needs more evidence because special treatment for allergy sufferers and public bans of nuts are getting out of hand.
A quick Google search reveals the beginnings of a Britannica article which also indicates that banning nuts is a bad idea since nut allergy deaths are not unacceptably higher annually than deaths from lightning strikes and bee stings, and because banning creates a climate of oversensitivity: http://www.britannica.com/bps/additionalcontent/18/35883327/Peanut-hysteria--or-is-it