Vacations are special, so it's O.K. to let children stay up a little past their bedtimes and indulge in the sickeningly sweet cereal that's banned from your pantry. Too many days of skipping naps and eating garbage, however, can result in cranky kids with upset stomachs. Keep some semblance of life as Junior knew it (for example, serve ice cream after dinner, not for breakfast). The same goes for discipline: loosen up, but maintain lines that cannot be crossed. If your child starts kicking the seat in front of her on the plane, state loudly and clearly that the behavior will not be tolerated. If nothing else, nearby passengers will be less peeved because they'll see that you're at least trying to enforce discipline. Walking kids up and down the plane aisle can help distract and tire them out, but don't do it when beverages are being distributed. Block the aisle and flight attendants will give you the hairy eyeball.