Baby luggage on a plane
With kids no older than 2 who travel on their parents lap, with the ticket price being 10-30% of the normal price (for regular airlines) or a fixed price depending on the destination (for no-frill airlines), no luggage is allowed or the limit is very low.
The airline ticket prices for children no older than 12 (depending on the airline) might be about 25-30% cheaper, with the luggage limit being the same as with adults or slightly lower.
The rule of thumb, however, is that for each young passenger a folding stroller can be brought along free of charge (airlines tend to require the stroller to be a one-piece type, like the so-called umbrella, which means that if we plan to fly a lot with our baby, it's a good idea to get ourselves the smallest and most lightweight stroller possible, like GB Pockit Plus - you can find its review here: https://www.babygeartested.com/gb-pockit-plus-2019-stroller-review/). In most cases they are transported in the cargo hold. Right before boarding the plane, the stroller is taken by an airport worker while on the runway and stored in the hold. The baby has to be carried in hands aboard the plane. Upon landing, the stroller is given back right after leaving the plane to make it possible to move around the airport freely.
Flying on a parent's lap
There are two ways airlines allow to fly with children no older than 2 – in a car seat on a separate airplane seat (usually from the age of 6 months up) or on a parent's or guardian's lap. The former solution entails extra costs though – having to pay for the seat. The latter option is much cheaper, the extra fee is usually 10-30% of a flight ticket for an adult passenger or the price is fixed depending on the destination chosen.
It entails a significant cut to the luggage limit, however, or lack of any registered luggage that the baby could be entitled to. In most cases, though, the luggage covers a baby seat or a carrier.
Every airplane is equipped with special baby suspenders that serve as seat belts, and they have to be fastened whenever a notification lits up telling the passengers to fasten their seat belts.
Flying in a car seat
Most of the time, babies can and actually should travel in car seats as, just like in cars, standard seat belts don't provide the little person with as much safety as a well-matched baby seat does.
If we choose to go with the baby seat option, we have to make sure if the seat also has an attestation for being used on planes. The seat or the packaging should have a special label for that. If the seat cannot be mounted (i.e. it is too wide), it can be transported in the cargo hold at an extra fee.
Food in the hand luggage and getting to board first
You can bring along baby food on a plane, including liquids – they are not subject to standard limitations for liquid transportations, although they have to go through a screening during the boarding process. In order to avoid additional screening, it is the best to bring powdered food. On most planes, it is possible to ask to have your food microwaved or to get hot water to prepare the food.
Plenty of airlines allow parents with babies to board the plane first so that they can properly accommodate themselves before other passengers arrive.