Having played an imaginary friend himself in the hit TV show Moone Boy, there are few people better equipped to advise youngsters on how to manage their own invisible mates than actor Chris O'Dowd.  And now London's Heathrow Airport has enlisted the help of the actor, producer, new Dad and all-round comedy genius in making a training video for staff about how to deal with young passengers and their non-existent pals in a friendly and accepting manner. So why the sudden interest in imaginary friends in general? Well. According to a new survey, 35 per cent of kids have one... and the majority of those (68 per cent) like to take them on holiday, which presumably raises many questions regarding seating arrangements and dining options. The video even features a crew member demonstrating how best to navigate security with your invisible mate in tow. Good to know. https://www.youtube.com/watch?t=59&v=kRHQ4kkBQ50