Wabarah bin Abdur-Rahman said:"Ibn 'Umar did not offer more than two rak'ahs when traveling, and he did not offer any prayer before or after that. It was said to him: 'What is this?' He said: 'This is what I saw the Messenger of Allah (ﷺ) doing.'"
أَخْبَرَنِي أَحْمَدُ بْنُ يَحْيَى، قَالَ حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا الْعَلاَءُ بْنُ زُهَيْرٍ، قَالَ حَدَّثَنَا وَبَرَةُ بْنُ عَبْدِ الرَّحْمَنِ، قَالَ كَانَ ابْنُ عُمَرَ لاَ يَزِيدُ فِي السَّفَرِ عَلَى رَكْعَتَيْنِ لاَ يُصَلِّي قَبْلَهَا وَلاَ بَعْدَهَا . فَقِيلَ لَهُ مَا هَذَا قَالَ هَكَذَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَصْنَعُ .
Nesai
The Book of Shortening the Prayer When Traveling • Hadith 1457