Plane ears popping

Hi, we're going on holiday end of May. My little one has probs with his ears so especially worried about them popping. When he was a baby I breastfed him, last year he had a fruit pouch, to stop his ears popping. What can I give him this year that will make him suck to stop them popping? He won't eat fruit pouches anymore and it's going to be tricky to take fresh milk or yoghurt and keep it cool. What are others giving their kids to stop ears popping when they're too young for sucky sweets/lollies?