The benefits and popularity of frameless soft sided pet carriers is their pliability and ability to conform to varying under seat configurations of modern aircraft. All airlines and rail actually have similar sizing requirements, and those are more stringent on narrow bodied aircraft than wide bodied aircraft, but yet the primary design of an airline capable bag is to comfortably fit your pet but yet conform to fit under the 8.5" seat. Many airlines will indeed show 8.5” as their height spec, but that is targeted for the older style hard shell carriers and not pliable frameless soft sided carriers. A carrier that is truly only 8.5” in height will only fit the smallest of kittens, puppies and bunnies. Also be aware that airlines state your pet must be able to stand and turn around, so you can see the dichotomy between airline specs and reality. Keep in mind, airline capable carriers are designed for your pet to be laying down, as most pets will need to do so to allow for fitting under the seat. Most of my bags are designed at about 18x11x11” (45x28x28cm) exterior measurement, as that is the optimal size for under seat capability on the widest variety of aircraft. All are designed with pet safety and comfort as a priority, and secondly with pliable fabrics that allow compression for under seat compatibility, so it’s mostly a choice of styling preference with each model.

Most of the standard sized models are about 16" on the interior length, while the larger Big Apple model is about an 18" interior. It is about 2” longer at 20” exterior than most airlines will spec, but it’s built for those pets where there is simply not an option for a smaller size. The Big Apple model has been on the market for a long period of time now, literally sold worldwide, and a very popular model. For those who desire a bag that is truly 9” in height to more easily meet under seat specs I can recommend to look at the Rhodium Mini model and the backpack models such as the Monterey and Aspen, all of which are designed and padded to lay on their short side for under seat use. Another option is the smaller Gold Series Mini, which is about an inch smaller all around than the standard sized models.Keep in mind that all of my airline capable models are frameless soft sided pet carriers, this is what allows for the pliability and ability to conform to various under seat configurations of modern aircraft and meet under seat specs. The fabric itself combined with the zipper closures is what primarily gives a soft sided carrier its structure.

The reality of airlines (and the TSA or equivalents) is there is no such thing as a blanket approval of a pet carrier model or brand, as there are many other factors involved, but there are indeed guidelines and standards which must be followed for in cabin compliance.