’my 20 year old is going on first holiday alone with friend to youth hostel in Spain beginning of July. As a family we have only had one holiday out of the uk (unfortunately covid and health problems meant no flying ) this was when he was toddler so he has no experience at all of finding his way in an airport, being in a plane , checking in and so on . I’ve advised him to check with airline for what can go in bags etc but he’s reluctant to find out more . Please help me to make an essential checklist, it’s been many years since I have been in a plane and I’m feeling pretty useless right now as a parent.