J.T.
Only one other person has mentioned it, but if a minor is traveling with only 1 parent, they need to provide a notarized letter of consent/authorization from the absent parent that they acknowledge that the child is traveling alone with the other parent. I took my 2 children to Ontario Canada without my husband (he was arriving a week later) and the Customs agent thanked me for being prepared with the letter.
I asked what would happen if I didn’t have the letter, and I was told that we would be detained until my husband was contacted and they spoke with him.