Some international airlines, including Australia's Qantas Airways and South Korea's two major carriers, Asiana and Korea Air Lines, shifted the route taken by flights operating over Ukrainian airspace months ago amid increasing tensions between Kiev and pro-Moscow rebels.
The airlines took extra security precautions despite no official ban from regulators on flying through the area, even as others continued to use the route.
The U.S. Federal Aviation Administration issued an order prohibiting U.S. aircraft from flying in the airspace over the Crimean region of Ukraine and parts of the Black Sea and Sea of Azov. Cathay Pacific Airways also said it adjusted its routes some time ago.
Several other airlines have continued to fly the route.