Airline seats allow passengers to travel in comfort but are also designed to ensure their safety. In recent decades some airline seats have been fitted with a variety of multimedia systems designed to keep passengers entertained, particularly during long, intercontinental flights. Airline seats are attached to rails running the length of the aircraft. This enables sets of seats to be moved forwards or backwards in accordance with the relevant technical documentation and offers airlines a quick and easy way to change the seating configuration and thus the number of passengers an aircraft can carry.
As a rule, the gap between seats in economy class is between 76 and 81 cm, while in first class it can be as much as 240 cm. The standard configuration of an Airbus A320 is 150 seats, although this number can be increased to a maximum of 180. Narrow-body airliners have different seating configurations ranging from 1+1, 1+2, 2+2, 3+2 to 3+3, while wide-body airliners such as the Boeing 747 and 777 or the Airbus A340 and A380 can have 3+3+3, 2+5+2 or 3+4+3. Wider seats offer more comfort than narrower ones, so naturally passengers prefer the former. Standard seat widths range from 43 to 46 cm. Seat width is of course conditioned by the internal width of the aircraft's fuselage and the number of aisles between seats. Narrow-body airliners have one aisle, while wide-body airliners have two. The aisles must be wide enough to allow a catering trolley to pass unhindered.
Where airlines allow passengers to purchase specific seats on their flights, these are usually the first to sell out. Less popular are seats in the very back row of the aircraft, since sometimes these do not allow passengers to recline the backrest. In the case of 3+3, 2+5+2 or 3+4+3 configurations, the middle seats are the least popular among passengers. Although these seats are the same width as those next to them, passengers have a fellow passenger on either side, which can be annoying and less comfortable, especially when the "middle" passenger wants to leave his or her seat.
In the case of a crash they can withstand loads of up to 16g, which greatly increases passengers' chances of survival in an accident. The seat frame is made of aluminium, while in recent times seat frames made of composite materials have been appearing on the market. The seat legs are designed to bend in the case of a crash so as to absorb the energy released. The most important thing is that they remain fixed to the seat rails and protect the passenger.
The cushion and backrest are made of polyurethane foam covered in fire-resistant fabric. The upper part of the seats is made of leather or fabric. The filler in the latest seats is made of more modern materials and is fire-resistant. Leather seats are more expensive but also more durable. They require less maintenance and give the cabin a more prestigious feel. They frequently come in shades of blue or grey, since these colours have a calming effect. The cost of airline seats ranges from a thousand euros for economy class seats to tens of thousands for first class seats. The latter have fully adjustable backrests that allow passengers to convert their already comfortable seat into a perfectly flat bed.