We flew in F on a 757 with a little dog across the aisle from us. It wasn't a problem. Mrs. Fredd suddenly noticed her ankle being licked on a flight in Y and she knows I'm nowhere near that athletic.

It turned out to be a fair sized lab service dog curled up behind her. The dog was very friendly with our little granddaughter who was with us so it wasn't an issue but I do sympathize with people who have serious allergies.