The FAA said it made the decision because Iran has de-escalated its military posture, reducing the danger to U.S. civil aviation operations.

The FAA had barred American pilots and carriers from flying in areas of Iraqi, Iranian and some Persian Gulf airspace since early January. The move was precautionary in nature to prevent civilian aircraft from being confused for ones engaged in armed conflict.

The FAA announcement said "there is sufficiently reduced risk of Iranian military miscalculation or misidentification that could affect U.S. civil aviation operations in the overwater airspace above the Persian Gulf and the Gulf of Oman." Those areas cover much of Kuwait, Saudi Arabia, Bahrain, the United Arab Emirates and Oman.

However, the agency said it still advises operators to exercise caution and avoid operating on air routes nearest to the Tehran Flight Information Region, an area understood to cover the airspace over Iran. The FAA said "the situation in the region remains fluid and could quickly escalate if circumstances change."

At the height of recent U.S.-Iran tensions, Iranian forces accidentally shot down a Ukrainian passenger jet over Tehran, killing all 176 people on board. The Jan. 8 shootdown followed Iranian ballistic missile strikes on two Iraqi bases that house U.S. troops. The Iranian attack was in retaliation for a U.S. airstrike in Iraq that killed a senior Iranian commander.

The downing of the Ukrainian jet was a grim echo of when U.S. navy forces accidentally shot down an Iranian passenger jet over the Persian Gulf in 1988.

Dubai International Airport has been the world's busiest for international travel for the past six years.