Special requirements are placed on flight crates. The flight crate must be escape-proof, leak-proof and bite-proof. Sufficient air circulation must be guaranteed. In addition, the dog or cat must have enough space in the box. If the criteria are not met, the respective airline can refuse the transport for the protection of the animal. There are special transport boxes that are IATA approved. These are approved by the airlines for transporting animals. You should look for this marking when buying a transport box that is also suitable for transport in an aircraft. Foldable transport boxes, for example, are generally not approved. With regard to size, it is important that the dog or cat can stand upright in the transport box, turn around and lie down in a natural position without any problems. Depending on the size and weight, the dog or cat may be allowed to fly in the cabin or must be placed in the transport compartment. Smaller dogs up to 6 kg and cats up to 8 kg may usually be taken along in their transport boxes in the cabin. However, the transport boxes may usually only have a size of 55 cm length x 40 cm width x 20 cm height or smaller. During the flight, the transport box is stowed in the footwell under the seat. The animal must not leave its transport box during the flight. Opening the transport box during the flight is also prohibited. In addition, many airlines only allow a certain number of animals in the cabin and avoid transporting cats and dogs at the same time. Therefore, it makes sense to register your pet as early as possible in order to have a better chance of it being allowed to travel with you in the cabin. Larger dogs weighing more than 6 kg or cats weighing more than 8 kg are transported in a special compartment in the hold. Make sure that the flight boxes for these animals are equipped with water and food containers that can be refilled from the outside. This is necessary so that the flight crew can refill or replace the water without having to open the box. Foldable boxes may not be used for transport in the cargo hold. The permissible weight in the cabin can vary between airlines, so it makes sense to check this with the airline before the flight.