This is just a question. . .I'm curious. As far as peanut butter and airborne particles. . .what if somebody was eating or had just eaten something with peanut butter and sneezed or coughed. Wouldn't that send some particles airborne?
I would not take peanuts or peanut products onto a flight. . .I think it would just be easier to avoid a potential hassle. I am also a firm believer in desensitizing. I rarely use hand sanitizer; I don't buy anti-bacterial soap; and I encourage my kids to play in the dirt. They rarely get sick. . . maybe once every 2-3yrs and then it's usually sinitus from the darn hay fever. My kids and I all have pretty bad hay fever. I have been buying local raw honey and it's been helping.

I feel for parents of kids with these severe allergies. It must be very scary.
As a side note, I'm allergic to latex. . .please dispose of those gloves properly.
ETA- Back to the topic. My kids like bagels with cream cheese, crackers and string cheese, dry cereal, beef jerky, and sub sandwiches.