It was narrated from Ibn 'Umar that if the Messenger of Allah ﷺ was in a hurry to travel, he would combine Maghrib and 'Isha'. (Using translation from Nasāʾī 598)
كَانَ رَسُولُ اللهِ ﷺ إِذَا جَدَّ بِهِ السَّيْرُ جَمَعَ بَيْنَ الْمَغْرِبِ وَالْعِشَاءِ