Ati was asked about the prayer of the traveler, and he replied, "I performed Hajj with the Messenger of Allah ﷺ, and he prayed two units. I performed Hajj with Abu Bakr, and he prayed two units. I performed it with Umar, and he prayed two units. And with Uthman during six, or eight, years of his caliphate, and he prayed two units."
حدثنا أحمد بن منيع حدثنا هشيم أخبرنا علي بن زيد بن جدعان القرشي عن أبي نضرة قال سئل
عن صلاة المسافر فقال حججت مع رسول الله ﷺ فصلى ركعتين وحججت مع أبي بكر فصلى ركعتين ومع عمر فصلى ركعتين ومع عثمان ست سنين من خلافته أو ثماني ثماني فصلى ركعتين
[Its chain is daif] Abu Dawud narrated it in Salat Safar, chapter, "When does the traveler pray in full," Hadith: 1229, from the hadith of Ali bin Zayd, and it is daif. Part of the hadith has very many corroborating narrations, including the previous hadith: 544.