I plan on flying from the west coast to the east and am going to either go with United or Frontier. I noticed on Frontier's website, they have an 8" max height of the traveling container (REF: Family & Pets). Yet, when I look up containers on Amazon, For example, this product: shows it is carrier approved, yet is 11" high, but Frontier only allow a max of 8". I see that most carriers are 11" high. Am I missing something here? Would I be able to get away with a carrier that is a few inches higher?