Lufthansa, Germany's flag carrier and the largest operator into hubs like Frankfurt and Munich, sets out a clear cabin-vs-hold split on its own website. In the cabin, only small dogs and cats are accepted, with the animal and its carrier together weighing no more than 8kg, in a soft-sided carrier no larger than 55 x 40 x 23cm that fits under the seat in front — one carrier per passenger, usually one animal per carrier.

Minimum age for cabin travel is 12 weeks generally, rising to 15 weeks specifically for travel from, to or via Germany, matching the country's own entry-age floor covered in the Documents section. A larger dog travels in the hold in an approved container instead, with Lufthansa capping combined numbers at two animals across cabin and hold together per passenger; anything beyond that, or a larger shipment, goes through Lufthansa Cargo as dedicated air freight.

Fees are charged per direction, including on connecting flights, and scale by route — roughly EUR 65-85 domestically up to EUR 125-145 on a long-haul intercontinental flight, per Lufthansa's own published ranges. Special regulations apply to fighting-dog breeds and snub-nosed (brachycephalic) breeds, and Lufthansa notes it may decline bookings on certain routes, including the UK and Ireland, so it's worth confirming the current rule for your specific route before booking rather than assuming it matches a flight you've taken before.