Flying with kids is so nerve-wracking. The most stressful part is gauging whether your kids will cry or have tantrums inside an enclosed metal tube for three hours. The second biggest challenge is keeping them occupied, which is much easier nowadays with tablets and iPads. A tertiary concern might be that your kids could make a mess on the plane. Luckily, if they don't throw up or have an accident, most messes are easy to pick up! At least, so we think. Semi-famous people are obsessed with twee…