As a disabled person flying with a European operator you are allowed to take two pieces of Mobility equipment in addition to your luggage allowance free of charge. This won’t count as part of your baggage allowance within the EU This includes walking aids like a walking frame and wheelchair. Check your airline’s website for more information.
Some airlines do not charge for transporting nappies, pads, specialised formula milks, car seats, booster seats, wheelchair trays etc. Although these & other items will be taken from you when you hand over your cases, the weight of these items is not counted when working out weight limits. Other airlines can charge for all the aforementioned items. Check with the airline that you are travelling with
Remember that if you use an air filled cushion that it can over inflate, affected by the changes in air pressure in the aircraft, so it is wise to check with your manufacturers instructions.