My son is severely allergic to peanuts. Before we ever flew with him we spoke to all airlines about how they would accommodate him. Only one we ever felt comfortable flying was Delta. Recently it has been said that Delta made changes to their allergen policy and we have seen stories of travelers having difficult times.
We just flew Delta round trip 6/18/2022. They allowed preboarding to wipe area, made announcements and came and spoke to us in person each time about the allergy. They asked about the severity, confirmed it was just peanuts and asked us if certain products would be ok to serve on board or in our area. Crews were extremely understanding and kind, telling us they wanted us to feel comfortable and safe.