Depending on who is the Custodial parent or if you have joint custody, you do not have to have a statement from him. If he has custody, you should make sure it is ok with him for you to take her. Hopefully, for you daughters sake she will be allowed to experience such a wonderful trip with you. If you are the Custodial parent, then the judge has deemed you solely responsible for the care of your daughter. Surely, he would want her to experience this trip regardless.