The conservative justices appeared sympathetic to the administration's contention that it can cancel humanitarian protections for Haitian and Syrian nationals.
The defense secretary sought to rebut lawmakers' criticism of the Trump administration's handling of the conflict, which has cost about $25 billion so far.
A trade group for the airlines is seeking $2.5 billion to help offset the big jump in jet fuel costs since the start of U.S.-Israeli attacks against Iran.
