This topic comes up every now and then on these boards.
As an FYI--I've flown US Air PHL to MCO and back at least five round trips since the beginning of the year, and they've been serving pretzels--no peanuts.
As someone who has nut allergies, I can sympathize. BUT, I think that the advice to take teh first flight should be taken.
Once you've gotten to lunch time, you've got a lot of parents who pack lunches for their kids, and it's often PB&J. There's no way of telling them in advance that they can't feed this to their kids--I think 99.9% of parents would cooperate and substitute something else if there was. I think that most parents are going to feed their kids, as much as it's not fair to your kid, it's also not fair to thirty other hungry bellies and potentially very unhappy kids. I wonder if there's a surgical mask or something along those lines that you could use for your son?
In all honesty, if I lived in Long Island and had a kid with that severe of an allergy, I wouldn't take the chance. I'd drive. Just my two cents.
Anne