The ban, which has already halted flights to the United States and affected many flights, was first imposed by President Donald Trump in January.
The Department of Homeland Security issued a temporary ban on travelers from six Muslim-majority countries, including Iraq, Somalia, Iran, Sudan and Syria.
Trump called the ban “not good for our country.”
Trump has since reinstated it.
The travel ban was challenged by the ACLU and others.
The Supreme Court is set to hear arguments in October.