How Travelers Pray When the Imam Is Replaced by a Resident

Question:
If a group of travelers is traveling and, for example, the time for the midday prayer catches up with them in a city along the way, and one of the travelers steps forward to lead, but after praying one unit of prayer he becomes ritually impure and leaves, and a resident imam steps forward to lead, what is the ruling regarding the travelers’ prayer? Do they complete their prayer, or do they shorten it?

Answer:
The substitute imam prays four units with them, and they complete the prayer with him; because the follower follows the imam, and the Prophet (peace and blessings be upon him) ordered the traveler who prays behind an imam to pray four units behind a resident imam. Ibn Abbas, when asked about this, said that people pray four units behind the imam, and if they pray in their camps while traveling, they pray two units. He said: This is the Sunnah. And when Uthman completed the prayer, the Companions completed it with him and prayed four units.
So these people whose imam became ritually impure, and one of them stepped forward and completed the prayer with them, they pray four units with him. And if he starts the prayer with them from the beginning, as a group of scholars said, he starts with them and prays four units with them, and they pray four units with him. And if he builds upon the first unit and prays three units, they pray three units with him and complete the prayer with him.

Question: But the intention differs; because they intended to shorten the prayer?

Answer: And if they complete the prayer with him, like the person on a ship or in an airplane who intended the traveler’s prayer, and then the airplane landed in his country, so he became one of the people of that country, he completes the prayer.