I'm 100% for allowing service animals of any kind, I think the airline should compensate passengers who are seriously inconvenienced by accommodating a service animal in space they've paid for -- and yes, I consider a dog under one's feet a serious inconvenience on a 4-hour flight. It's the airline, not the passengers, who has a duty to accommodate the disabled person. Other passengers should politely tolerate the accommodation but should get an upgrade on their next flight or some other recognition of the imposition on their space.