Hadith 980
Abu Hurairah (May Allah be pleased with him) reported:
عن أبي هريرة رضي الله عنه قال: قال : رسول الله صلى الله عليه وسلم : " ثلاث دعوات مستجابات لا شك فيهن: دعوة المظلوم، ودعوة المسافر، ودعوة الوالد على ولده" ((رواه أبو داود، والترمذي وقال: حديث حسن)) وليس في رواية أبي داود: “على ولده”
The Messenger of Allah (ﷺ) said, "Three supplications are answered without doubt. The supplication of the oppressed, the supplication of the traveller, and the supplication of the parent for his son." [At- Tirmidhi and Abu Dawud].
In plain words
The Prophet named three prayers that are surely answered: that of the oppressed, of the traveller, and of a parent for their child, so a traveller should make good use of this time of accepted supplication.
Reference : Riyad as-Salihin 980 In-book reference : Book 7, Hadith 25