(11) باب مَنْ لَمْ يَتَطَوَّعْ فِي السَّفَرِ دُبُرَ الصَّلاَةِ وَقَبْلَهَا
Narrated Ibn `Umar:
I accompanied Allah's Messenger (ﷺ) and he never offered more than two rak`at during the journey. Abu Bakr, `Umar and `Uthman used to do the same.
Reference: Sahih al-Bukhari 1102
In-book reference: Book 18, Hadith 22
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 2, Book 20, Hadith 206