Quiz question: What’s north of Iraq and south of Ukraine? If you said Turkey or the Black Sea, you’d be right. Another correct answer this week would be “a whole lot of airplanes.”

That’s because the Federal Aviation Administration last week banned flights by U.S. airlines over Iraq after the U.S. began airstrikes against militant forces, troops that already had captured all manner of weaponry that the Pentagon had entrusted to the Iraqi army. Many European carriers followed suit, and their Middle Eastern counterparts also began skirting around Iraq on Monday.

With Ukrainian airspace already put off limits by the FAA after the Malaysia Air Boeing 777 was shot down last month, and Syria and Gaza both in turmoil, the path between Europe and Asia narrowed like the neck of an hourglass. The airspace over Iraq has been a route heavily traveled by commercial airlines. On Monday, the few planes in the air over Iraq were headed in or out of Baghdad, and most were flown by Iraqi Airways. A similar situation existed over eastern Ukraine.

Russian President Vladimir Putin last week threatened to retaliate against Western sanctions by banning Western airlines from Russian airspace. Russia’s air transport agency said European airlines save about $30,000 per flight in fuel and fees by flying over Russia. But those flights across Siberia net up to $300 million a year for Aeroflot, the state-owned Russian airline.

While there have been no more rumblings from the Kremlin on the subject this week, U.S. carriers began making contingency plans after Putin’s announcement. If that airspace is closed, they would feel the impact less than Europeans, but Delta Airlines said it might have to reroute a dozen flights.

That airspace north of Iraq and south of Ukraine could become even busier.