The Prophet ﷺ set out on Thursday for the Ghazwa of Tabuk and he used to prefer to set out (i.e. travel) on Thursdays. (Using translation from Bukhārī 2950)   

أَنَّ النَّبِيَّ ﷺ «خَرَجَ فِي غَزْوَةِ تَبُوكَ يَوْمَ الْخَمِيسِ وَكَانَ يُحِبُّ أَنْ يَخْرُجَ يَوْمَ الْخَمِيسِ»  

[Machine] The Messenger of Allah ﷺ rarely showed his face to others. Until the Battle of Tabuk, when the Messenger of Allah ﷺ stood up and made his intentions known to the people. He wanted the people to prepare their weapons for battle. So the Messenger of Allah ﷺ became a warrior on Thursday.  

كَانَ رَسُولُ اللهِ ﷺ قَلَّمَا يُرِيدُ وَجْهًا إِلَّا وَرَّى بِغَيْرِهِ حَتَّى كَانَتْ غَزْوَةُ تَبُوكَ فَقَامَ رَسُولُ اللهِ ﷺ فَجَلَّى لِلنَّاسِ فِيهَا أَمْرَهُ وَأَرَادَ أَنْ يَتَأَهَّبَ النَّاسُ أُهْبَةَ غَزْوِهِمْ فَأَصْبَحَ رَسُولُ اللهِ ﷺ غَازِيًا يَوْمَ الْخَمِيسِ مُخْتَصَرٌ  

It was rarely that the Messenger of Allah ﷺ set out on a journey on any day but on a Thursday. (Using translation from Abū Dāʾūd 2605)   

«قَلَّمَا كَانَ رَسُولُ اللهِ ﷺ يَخْرُجُ فِي سَفَرٍ جِهَادٍ وَغَيْرِهِ إِلَّا يَوْمَ الْخَمِيسِ»