As a rule, all airlines are allowed to carry free folding light stroller for free with a child up to two years of age, and in some airlines, the carriage is allowed to transport also for older children (sometimes free of charge, sometimes the stroller is accepted as luggage). If the carriage is transported for free, the stroller may be limited in weight and size to the sum of three measurements. For example, in International the weight of the stroller is allowed up to 20 kg, and in domestic transit the weight of the stroller should not be more than 4.5 kg, the size not exceeding 53 * 27 * 97 cm. Depending on the internal rules of the airline, the carriage must be delivered at the check-in counter, Before entering the sleeve or before boarding an aircraft, or you can take it with you to the aircraft cabin (for details, it's better to check in advance, then there will be no surprises at the airport).