You can honor your parents without agreeing with every play they call.

Honor and agreement are two separate things, and collapsing them makes both harder. You can treat your parents with respect, tell them the truth, and still hold a different view about the decision in front of you. Pretending to agree is not honor, it is management, and it usually ends with resentment on both sides.

Say the disagreement plainly, once, without contempt in it. Ask what they are actually worried about, because the worry is usually the real message. Then keep the relationship warm regardless of whether they come around, since that part is yours to decide.