Is voluntary prayer permissible while traveling, whether descending or moving?

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Voluntary prayer is permissible while traveling, whether descending or moving. The Messenger of Allah, peace be upon him, performed voluntary prayer upon his mount wherever it faced, signaling with his head. This practice was narrated by Ibn Umar, and similar reports exist from Jabir and Anas, all of which are agreed upon (Muttafaqun 'Alayhima). Furthermore, the Prophet (PBUH) prayed eight rak'ahs when he entered Makkah on the day of its conquest, as narrated by Umm Hani bint Abi Talib. Ali, may Allah be pleased with him, reported that the Prophet (PBUH) would perform voluntary prayers while traveling. This permission extends specifically to the two rak'ahs of Fajr and Witr, as Ibn Umar narrated that the Prophet (PBUH) performed Witr on his camel. Also, when the Prophet (PBUH) overslept the Fajr prayer until sunrise, he prayed the two rak'ahs of Fajr afterward, which is agreed upon.