If you're unlucky enough to be flying sitting next to some selfish parent's screaming kid and that parent follows today's standard parenting approach of allowing their offspring to do anything at any time, then I can thoroughly recommend the Bose kit, or, if you don't have it, anything by Insomnium played loudly.
AC, because this type of parent gets a bit spiteful when their inbred sense of entitlement is challenged.
Biting the hand that feeds IT
