Taking a cat or dog on holiday within Europe is far easier than most travellers assume – but the fine print varies wildly between carriers. A new comparison by AirAdvisor reviewed the pet policies of 22 European airlines, scoring them on cabin access, hold travel, fees and even whether pets are welcome in airport lounges.

The broad picture: most European airlines let small pets (usually up to 8kg including carrier) ride in the cabin for a fee, while bigger animals go in the hold – sometimes at eye-watering prices. Air France charges anywhere from €100 to €750 for hold transport depending on the pet's weight, and KLM's fees run from €70 to €500 each way.

A few carriers stand out for flexibility. Finnair allows two pets of the same species in one carrier and even takes hedgehogs, tortoises and rabbits from EU countries – ferrets can travel in the hold from anywhere. LOT Polish Airlines is unusual in letting pets roam its lounges under supervision, rather than requiring them to stay in carriers. Lufthansa, Austrian, Brussels, SAS and TAP all cap out at two pets per passenger, and Aegean lets pets into its lounges and charges from just €35 on domestic Greek flights.

The catches are easy to trip over. Flat-faced breeds like bulldogs and pugs often face extra restrictions because of breathing risks at altitude. Pets under 12 weeks are generally barred, and Air France requires 15 weeks for international routes. Snubbing premium cabins doesn't help either – business class is often less pet-friendly than economy. Codeshare flights and multi-airline connections complicate things further, since each carrier's rules apply to its leg.

Destination matters most of all. On routes to the UK, USA, Australia and Hong Kong, some airlines only accept pets as separate freight – so your animal travels with cargo, not with you. Book well ahead too: Finnair charges less if you register your pet at least seven days before departure.

The bottom line for pet owners: pick a direct flight on a single airline, check the combined weight limit early, and budget €35–€170 for cabin travel on most European routes. If your dog is a pug or your holiday is in Hong Kong, read the policy twice before booking.