If you have allergies, I’d guess you’d have to call ahead and tell them, no animals. I bet you can’t do that, though.
BTW I have 2 dogs and a cat. Their dander does not bother me, but other animals dander does.
( i seriously may never get on another airplane)
Just don’t seat me next to a liberal.
Even if an animal is not on the plane, there can be plenty of dander. Anyone with a pet can have it on their clothing and/or bags.
As an aside, I would be more than willing to pay for a seat for my hypo-allergenic dog and have him in a kennel, if airlines would do so. I would far rather have a contained, likely, sleeping dog near me, than a many other types of passengers. I just don’t fly anymore unless absolutely necessary.