Thank you Cruiser for your reply. The restrictions were placed as a result of human error and/or system failures and had no connection to crate height. Shortly after implementing the changes United realized certain unintended consequences. Thankfully they had to make exceptions for military families traveling between duty stations. This confirmed the fact that the new policy was a business decision not one based on the care and concern of canine travel as professed. Animals can still travel on a United flights with a few breed exceptions. Limiting the size of the crate makes no sense. The plane certainly did not get smaller all of a sudden.