Dwindling flight options remain as Ukraine faces uncertain civil aviation future

As the situation in Ukraine has deteriorated, there are still commercial flights — for now.

As Russian troops began entered separatist-held areas of eastern Ukraine in the past 24 hours, there has been no significant change in air service to Ukraine's capital, Kyiv, and its two main airports, Kyiv Boryspil (KBP) and Kyiv Zhuliany (IEV), which represent the main aviation hubs for the country.

Previously, some European carriers announced they were suspending service to Kyiv. KLM terminated its service to Amsterdam Schiphol (AMS) last week, and sister airline Air France made the same announcement yesterday for its service to Paris Charles De Gaulle (CDG). The three main Lufthansa Group carriers, Lufthansa, Swiss and Austrian, have also suspended service to Ukraine's capital.

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There are still plenty of airlines that operate to Ukraine, but given the country's uncertain security situation going forward, it's unclear how long this service will continue. Ukraine International Airlines, the nation's flag carrier, is still operating some service, but it ferried five Boeing 737s to Spain last week. Other airlines that continue to operate include major European ultra-low-cost carriers Ryanair and Wizz Air as well as Qatar Airways, Turkish Airlines, Air Baltic, LOT Polish Airlines and FlyDubai. No American carriers fly to Ukraine.

With so much uncertainty, the U.S. Embassy in Kyiv is urging U.S. citizens to depart.

"There is a strong likelihood that any Russian military operations would severely restrict commercial air travel," the embassy wrote in an alert.

Ukraine is the largest country entirely in Europe, by area. The separatist areas seeing Russian military action are approximately 350 to 400 miles east of Kyiv. This includes the site of the 2014 shootdown of Malaysia Airlines Flight 17, which killed 298 people. As a result of the shootdown, many airlines have avoided overflying that area since that time.

The decision to terminate service — or even to avoid Ukrainian airspace — comes down to the risk assessments airlines make and, especially, insurance coverage, said Robert Mann, an aviation consultant and former airline executive.

"Many of the airlines involved who would normally fly through that airspace would lose their insurance coverages — their commercial insurance coverages for passenger liability, aircraft hull, etc.," Mann told TPG in an interview.

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Further deterioration of relations with Russia could affect overflight permits for existing Western carriers, Mann warned. Russia is by far the largest country in the world by area, and its airspace is transited by many airlines operating polar routes. But Russia could also stand to lose lucrative overflight fees if it bars Western airlines from operating in its airspace.

"That of course makes the problem not just a Europe-to-Southeast Asia sort of problem," he said. "It makes it a West Coast, of North America and in some cases, Europe to Asia, over the poles problem. And that makes the problem much wider, but of course, it also costs Russia much more in terms of air navigation charge losses."