The Messenger of Allah ﷺ used to perform the witr prayer while riding his mount.
أخبرنا عبيد الله بن سعيد قال حدثنا يحيى بن سعيد عن عبيد الله بن الأخنس عن نافع
أن رسول الله ﷺ كان يوتر على الراحلة
No references are available.
Bukhari narrated it, Witr, Chapter on Witr while traveling, no. 1000 and no. 1095, and Muslim, Prayer of the Traveler, Chapter on the permissibility of performing the voluntary prayer while riding during travel in whatever direction one faces, no. 700, through the hadith of Nafi, with similar meaning.