Following the downing of Malaysia Airlines 17 over Ukraine on Thursday, the Federal Aviation Administration (FAA) expanded an existing regulation that prohibited certain flights from operating in the region.
The FAA has been regularly issuing airspace restrictions and prohibitions for U.S. airplanes that travel through potentially hostile airspace. As of Friday, July 18, here are the places for which the agency has issued flight prohibitions and restrictions:
Note that in many countries where there is an ongoing conflict, the FAA has restricted flights below a certain height, due to the risk of attacks from small arms, rocket-propelled grenades, anti aircraft fire and MANPADS.
In Iraq and Somalia, the FAA prohibits flight operations at or below 20,000 feet, except where necessary for takeoff in an adjacent country. In the Congo, aircrafts are advised not to fly at an altitude of less than 15,000 feet. In Egypt's Sinai Peninsula, FAA warns against flight operations at or below 24,000 feet.
You can read here in detail, the advisories issued for each of the countries highlighted above.