Jabir (May Allah be pleased with him) reported:
When we ascended (a height) we would proclaim: "Allahu Akbar (Allah is Greatest)," and when we descended (from the height) we would proclaim: "Subhan Allah (Allah is free from imperfection)."'[Al-Bukhari].
App reference: Book 8, Hadith 20
Arabic/English book reference: Book 8, Hadith 975