My husband and I will be flying out over Thanksgiving through PHL & MCO. We both have KTN's. We will be bringing our 22 year old son with us, he is medium-functioning autistic, and does not have a KTN[/QUOTE]

Not sure how you got your KTNs, but have you thought of applying for Global Entry for him? Though if he doesn't fly much it may not be worth it.