The latest kennel rules state that "kennels can’t exceed the under seat dimensions of any aircraft included in your journey." Is there some place that lists the under-seat dimensions by aircraft type?

I have historically travelled with a medium sherpa carrier that easily fits underneath the seat on aircraft like 738, 32B, E75, etc. I have bought a large sherpa carrier that is .75 inches wider and 1 inch taller, and my dog actually enjoys sitting in it. It is collapsible, so it doesn't have to meet the hard under-seat requirements, but having a list of dimensions by aircraft would be helpful.

In any case, I'll probably take the carrier alone without my dog as a personal item just to see how it fits, and limit my travel on larger aircraft such as the 738 or 32B whenever I travel with my dog.