As I've said before:
The bottom line is that flying with a peanut allergy and being exposed to potential sources of peanut in the cabin is not likely to represent an increased risk to the peanut allergic flier. There is no evidence to support peanut vapor as a cause of reactions or that peanut dust itself circulates and causes reactions.
References:
Simonte SJ, Ma S, Mofidi S, Sicherer SH. Relevance of casual contact with peanut butter in children with peanut allergy. J Allergy Clin Immunol 2003;112:180-2.2. Perry TT, Conover-Walker MK, Pomes A, Chapman MD, Wood RA. Distribution of peanut allergen in the environment. J Allergy Clin Immunol 2004;113:973-6.3. Brough HA, Makinson K, Penagos M, et al. Distribution of peanut protein in the home environment. J Allergy Clin Immunol 2013;132:623-9.4. Jin JJ, Dorn JM, Yunginger J, Ott NL. Ara h 2 is detectable on surfaces of commercial airplanes. J Allergy Clin Immunol Pract. 2018 Jun 4. pii: S2213-2198(18)30349-0. doi: 10.1016/j.jaip.2018.05.027.5. Blom WM, Vlieg-Boerstra BJ, Kruizinga AG, van der Heide S, Houben GF, Dubois AE. Threshold dose distributions for 5 major allergenic foods in children. J Allergy Clin Immunol 2013;131:172-9.6. Blumchen K, Beder A, Beschorner J, et al. Modified oral food challenge used with sensitization biomarkers provides more real-life clinical thresholds for peanut allergy. J Allergy Clin Immunol 2014;134:390-8.7. Ballmer-Weber BK, Fernandez-Rivas M, Beyer K, et al. How much is too much? Threshold dose distributions for 5 food allergens. J Allergy Clin Immunol 2015;135:964-71.8. Hourihane JO, Allen KJ, Shreffler WG, et al. Peanut Allergen Threshold Study (PATS): Novel single-dose oral food challenge study to validate eliciting doses in children with peanut allergy. J Allergy Clin Immunol 2017;139:1583-90.9. Sicherer SH, Furlong TJ, DeSimone J, Sampson HA. Self-reported allergic reactions to peanut on commercial airliners. J Allergy Clin Immunol 1999;104:186-9.10. Greenhawt MJ, McMorris MS, Furlong TJ. Self-reported allergic reactions to peanut and tree nuts occurring on commercial airlines. J Allergy Clin Immunol 2009;124:598-9.11. Comstock SS, DeMera R, Vega LC, et al. Allergic reactions to peanuts, tree nuts, and seeds aboard commercial airliners. Ann Allergy Asthma Immunol 2008;101:51-6.12. Greenhawt M, MacGillivray F, Batty G, Said M, Weiss C. International study of risk-mitigating factors and in-flight allergic reactions to peanut and tree nut. J Allergy Clin Immunol Pract 2013;1:186-94.