The literature seems to suggest that the frequency of individuals claiming to be susceptable to areosolized peanuts is far greater than the estimates of the prevalence of this type of extremely rare reaction to non ingested allergens.
"According to the 2000 appropriations act, no federal money can be used to ban peanuts or require a peanut-free buffer zone in any air carrier until at least 90 days after Congress and the DOT receive a peer-reviewed scientific study demonstrating that people with peanut allergies can have a severe reaction if they are exposed to small quantities of the allergen while on a plane."
http://www.foodallergy.org/page.aspx?pid=1030