My Schäferhundmix (now 1 1/2, about 28 kg) has now flown a few times very relaxed in this box. There was so far no difficulties with the airlines (Air France, Brussels, Lufthansa and others), or airports. For transit, the box can be loaded onto a baggage trolley; the added ordered set of rollers, although I have always carried a precaution in hand luggage, but not yet used. The only weak point is the closure clips, of which I now and then ever one is canceled. However, the clips can be ordered conveniently; Again, I would carry a few in reserve in their hand baggage for transfer connections. My dog uses its box (with out hinged door) as a place to sleep in the house and gladly gets back as soon as it hits the road.