Conditions of Carriage by European airlines.

 ! According to IATA rules the following countries belong to Europe: Albania, Algeria, Andorra, Armenia, Austria, Azerbaijan, Belarus, Belgium, Bosnia and Herzegovina, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark (with exclusion of Greenland), Estonia, Faroe Islands, Finland, France, Georgia, Germany, Gibraltar, Greece, Hungary, Iceland, Italy (and Vatican City), Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, Montenegro, Morocco, Netherlands, Norway (including Svalbard and Jan Mayen), Poland, Portugal, Republic of Ireland, Republic of Macedonia, Republic of Moldova, Romania, Russia (European part, west of the Urals), San Marino, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tunisia, Turkey, Ukraine, United Kingdom.

* Hand luggage rules of some airlines are very different from all the others:
easyJet, Iberia, Iberia EXPRESS: no weight limit for hand luggage, the main thing is that you can place it into the overhead locker yourself.
British Airways: the weight of one piece of hand baggage (for "any essential items you may need during your flight" :) can not exceed 23 kg.
! VIM-Airlines permitted transportation of hand luggage with max weight only of 5 kg for economy class (and 10 kg for business).
And Onur Air rules specifically describe the transportation of gold as hand luggage, if its weight exceeds 8 kg or size 25x45x56cm, then the relevant passenger should purchase a second seat (extra seat) for the gold :).

* On most flights you can take in addition to officially allowed carry-on baggage another small item (handbag, laptop, camcorder, umbrella, etc.).
For example, Aeroflot allows to transport a backpack as an additional "small item" (of no more than 5 kg and 80 cm in the sum of three dimensions). But lately more and more airlines demand to weigh these additional items together with hand luggage.
! TAP Portugal: small items are limited not only in size, but also in weight (0.2 kg).

* In most cases you won't be able to cancel baggage registration and prepaid extra baggage is not refunded if you cancel your flight.

 * Carriage of skiing equipment: usually fee is for one-way journey and includes the whole set of sporting equipment even if it is packed in separate bags, e.g. 1 pair of ski + ski boots + helmet, but
! Finnair: packed separately ski boots (helm etc.) considered to be additional piece of baggage.

* Most airlines will accept your bicycle packed in a bicycle travel case with the wheels and pedals removed and handlebars turned parallel or packed in cardboard, but some of them require to deflate the tires.

* Transportation of animals can be difficult and costly. The airline can refuse to transport cats and dogs of brachycephalic breeds (such as bulldog, shih-tzu, pug, boxer, Pekingese, etc.), rodents, arthropods, reptiles, fish, etc.
! TAROM: for pets are carried in the aircraft cabin the size of the container must not exceed 93 cm in the sum of three dimensions 42х30х21 (93) cm and its max weight (with pet/pets) is 5 kg.
! Norwegian Air Shuttle: when carrying pets on connecting flights (Norway only), your transfer time between flights must be longer than 1 hour and shorter than 2 hours.
! KLM: If a pet travels as check-in baggage and the transfer at Amsterdam Airport Schiphol takes longer than 2 hours, an extra fee of €150 (or $/CAD 200) will apply.
Not all airlines can carry your pet to/from UK: the list of approved airlines and airports from gov.uk.

* For the carriage of special baggage (pets, sports equipment, musical instruments, oversized, overweight baggage and so on) you'll have to receive a consent from the airline in question, so you must always make a reservation by telephone or online (some airlines require passengers to make a reservation exclusively by phone) and on the whole not later than 24-48 hours before departure.

* More information on Traveling with Pets you'll be able to find on these pages:

• Pet-Friendly Airlines (Review of pet travel policies of largest airlines worldwide),
• Flying with Pets using European Airlines,
• Traveling with Pets by American Airlines,
• Pet Transportation by Asian Airlines
• or Flying with Cats.

* For fragile and oversized musical instruments an additional seat may be reserved (standard price for adult). In other cases the carriage is regulated by the general baggage rules (including free baggage allowance).
! Ural Airlines: musical instruments are not included in the free baggage allowance and are paid for separately.

* Transportation fees will be lower on domestic flights of airlines, then goes traveling within a specific continent. Usually you'll have to pay more on intercontinental routes.

* Usually indicated charges are per one way only.

* Sometimes it's hard to determine even an approximate fee without knowing an exact route (as for Turkish Airlines).

* If you are using flights with transfer time at an airport exceeding 2 hours, you're sometimes required to pay for your baggage an additional fee.

* Usually the weight of one piece of baggage must not exceed 32 kg. The items weighing more can still be transported as cargo/freight for an extra fee.

* Often the baggage of children under two years of age traveling on an adult's lap free of charge is limited, at the same time children under two occupying a separate seat have the same free baggage allowance as adult passengers.

* Purchasing extra bag / excess baggage online in advance, through contact centers or specialized agencies (not at the airport) often provides a significant (20-70%) discount (Aegean Airlines and Air Serbia: up to 70%; IBERIA, IBERIA EXPRESS: 50%; easyJet: £12-22 online and £32-45 at the airport), you should remember that these fees are often nonrefundable.

* According to IATA (the International Air Transport Association) recommendations:
carriage of small lithium battery-powered vehicles (airwheel, solowheel, hoverboard, mini-segway, balance wheel) is not allowed for batteries exceeding 160Wh, allowed for batteries with rating less or equal 100Wh, and for ones exceeding 100Wh but less or equal 160Wh allowed with prior notification and approval of the operator (in either checked or carry-on baggage); but many airlines prohibit transportation regardless of battery rating.
Usage of electronic cigarettes is prohibited (can be stored in carry-on baggage).
On the page of IATA you can find more info on carriage of dangerous goods.

* And about some other fees for optional services: one has to pay for seat reservation, extra leg room, often also for airport or phone booking and so on.
! Ryanair airport check-in costs €55 or £55.
! Pobeda (a Russian low-cost carrier) took earlier €35 or ₽2000 for a bag with duty free purchases. Now you can take it on board free of charge, but only if it's not larger than 36x30x27 cm.
! Norwegian Air will take £4 for a travel blanket.