It has been narrated from ʿAṭiyyah al-ʿAwfī, from Ibn ʿUmar, that the Prophet ﷺ used to perform voluntary prayers while traveling, both before the obligatory prayer and after it.(1)

And it has been authentically established from the Prophet ﷺ that he used to shorten the prayer while traveling, as did Abu Bakr, ʿUmar, and ʿUthmān during the early part of his caliphate.(2)

The practice is upon this according to most of the people of knowledge among the Companions of the Prophet ﷺ and others.

And it has been narrated from ʿĀʾishah that she used to complete the prayer in full while traveling.(3)

The practice is upon what has been narrated from the Prophet ﷺ and his Companions, and this is the view of al-Shāfiʿī, Aḥmad, and Isḥāq — except that al-Shāfiʿī says: Shortening is a concession for him while traveling, and if he completes the prayer in full, it suffices for him.

553 — Aḥmad ibn Manīʿ narrated to us, saying: Hushaym narrated to us, saying: ʿAlī ibn Zayd ibn Judʿān informed us, from Abū Naḍrah, who said:

ʿImrān ibn Ḥuṣayn was asked about the prayer of the traveler, and he said: I performed Hajj with the Messenger of Allah ﷺ, and he prayed two rakʿahs; and I performed Hajj with Abu Bakr, and he prayed two rakʿahs; and with ʿUmar, and he prayed two rakʿahs; and with ʿUthmān for six years of his caliphate — or eight years — and he prayed two rakʿahs.(4)

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(1) It will come later from the author at no. (559).
(2) Its takhrīj has preceded at no. (552).
(3) Narrated by al-Bukhārī (1090) and Muslim (685) (3).
(4) Ṣaḥīḥ bi-ghayrihi (authentic due to corroborating evidence), and this chain is weak due to the weakness of ʿAlī ibn Zayd ibn Judʿān. =