As I mentioned in #1. It seems to be such an easy question. But first you have to define 'kids'. Whose? how old? Then define ID. Gov't issued? birth cert? Passport? Then how to fly? Commercial, private, charter, sightseeing? Domestic or Int'l? Then you throw in the spotty and changing parameters of TSA rule enforcement and the various airlines policies on carrying minors.
There is no simple, quick answer to the OPs question. Be prepared for the most stringent enforcement and happy when asked for less.
Jim