Help! Not flown for a few years, we are used to loading the car up to the max and getting on a ferry. is 15kg x4 enough for my family of 4 for one week in Spain? I bought a luggage scale and it is either faulty or I have gone way over with only a bare minimum mock up case load!! I already plan to buy shampoo etc when we get there so can't see how I can cut back. Advice please!