Ukraine's ban on Russian commercial flights in its airspace could prevent a return to the fighting between the two former Soviet republics that has claimed 8,000 lives since last year.
It could also cement the tensions that gave rise to the conflict in the first place.
"The good news is, this is much preferable to a major outbreak of fighting in Eastern Ukraine again," Steven Pifer, a former United States ambassador to Ukraine who is now a senior fellow at the Brookings Institution, said. "It's not going to help with what the sides ultimately need, which is really a political settlement."
Currently, the two sides are fitfully upholding a ceasefire — occasionally clashing and shelling each other — in the war that erupted last year after Russia's annexation Crimea and its support of separatist movements in Eastern Ukraine.
Ukrainian Prime Minister Arseniy Yatsenyuk announced the flight ban on Wednesday and suggested it would prevent Russian aircraft from antagonizing relations between the countries. Ukraine had already prohibited Russian flights from its airports.
"Russia might use Ukrainian airspace to stage provocations," said Yatsenyuk, according to reports. "This is an issue of our country's national security — a response to the Russian Federation and its aggressive actions."
Yatsenyuk didn't get specific about those provocations, but he didn't have to.
Recently, Russian planes have repeatedly skirted or ventured into the airspace of North European countries, prompting NATO to beef up security in the region. This week, NATO-member Turkey shot down a Russian warplane for flying over Turkish territory, reminding Moscow about the risk of crossing those boundaries.
The flight ban came on the same day Ukraine said it would not order natural gas this winter from Russia, instead opting for European supplies. That move undercut a key Russian tool in wielding influence over the country.
The ban also comes a few days after unidentified saboteurs in Ukraine blew up electric transmission lines to Crimea, plunging the now-Russian territory into darkness. Russia retaliated by halting coal supplies to Ukraine, demonstrating that Moscow has numerous levers it can pull when trying to intimidate Kiev.
Seton Hall University International Relations Professor and Wilson Center Fellow Margarita Balmaceda said the ban and shifts in energy policies reflect how the relationship between the Ukraine and Russia might not necessarily be as violent as in the past, but is nonetheless hitting a new low.
"Even when Ukraine and Russia have been in a conflict, the economic relations between these two states have continued," she told VICE News. "Ukrainian in particular has continued to purchase coal from Russia because it has few other options. Now the question is, will this economic side be largely restricted?"
Aviation expert Steve Jaffe, who authored Airspace Closure and Civil Aviation, said Ukraine's flight ban could wreak havoc with Russia's commercial airlines.
Flights heading southwest to Rome, North Africa, and elsewhere must now go through Belarus or Turkey. If airlines opt for the former route, their planes would need to go in the wrong direction before turning to their final destination. If they take the latter route, then they need to somehow avoid Iraq, Syria and other war-torn regions to the south of Russia that nearly international air carriers now avoid, said Jaffe. Neither option is ideal, he added.
"The available airspace is becoming more like Swiss cheese, with more holes than cheese, in the Middle East," Jaffe said. "Airlines try to make those routes as straight as possible. It's a simple matter of economics. The longer the plane is in the air, the more it costs."
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