Hello There-
I can tell you that last October I took my 3 boys (then ages: 14, 10 & 6) to Mexico, actually Puerto Vallarta and I was told by the airline that first we needed passports (which BTW both parents must sign the application) and second If they had any kind of school ID they should bring it. Out here (San Diego) all of our Jr Highs & High School issue ID's so my oldest son was able to use that. My other two, they just asked them their names at the secruity check point.
That was for an internation flight.......if your staying demostic then bring ID's if you have them, otherwise don't worry about it.
hth
denise