WASHINGTON—A U.S. military proposal for arming Syrian rebels also calls for a limited no-fly zone inside Syria that would be enforced from Jordanian territory to protect Syrian refugees and rebels who would train there, according to U.S. officials.

Asked by the White House to develop options for Syria, military planners have said that creating an area to train and equip rebel forces would require keeping Syrian aircraft well away from the Jordanian border.

...