Ukraine's neighbor Moldova has also closed its airspace, as has part of Belarus. Meanwhile the US government's Federal Aviation Administration has told US pilots to avoid "the entire country of Ukraine, the entire country of Belarus and a western portion of Russia."

The UK has banned civilian Russian aircraft from its airspace. In response, Russia has banned British aircraft from its airspace.

Poland and the Czech Republic announced plans on Friday to close their airspace to Russian airlines as well.

Countries including the United States and the United Kingdom have advised their citizens to leave Ukraine, and both the US and the UK have advised against all travel to Ukraine.

The European Union Aviation Safety Agency, known as EASA, has warned of a "high risk" to civilian aircraft flying near the Ukrainian border.

Here's what we know about how travel in Eastern Europe and Russia might be impacted in the wake of the conflict.

Can I still fly to Eastern Europe?

Air traffic is still moving outside of severely affected areas. As well as bordering Russia, Ukraine also neighbors Belarus, Poland, Slovakia, Hungary, Romania and Moldova, as the map above illustrates.

EASA doubled the size of the warning zone around Ukraine on February 25, fearing "mid-range missiles penetrating into controlled airspace."

The zone expanded from within 100 nautical miles to within 200 nautical miles of the Ukrainian border with Russia. EASA says the expanded area now factors in the "risk posed by the threat of missile launches to and from Ukraine."

All countries bordering Ukraine were already on the US Centers for Disease Control and Prevention's Level 4 list of highest-risk Covid-19 destinations for travel. The US government also warns against traveling to Belarus and Moldova due to the conflict.

Florida-based travel adviser Gwen Kozlowski, a specialist in travel to central Europe and president of travel agency Exeter International, told CNN Travel on February 24 that her agency has had questions from travelers with upcoming trips to Poland, but no cancellations so far.

"We have guests traveling at the end of March and into April in Poland, but that's over a month out. It's impossible to say now how this will evolve. We're basically in wait-and-see mode," Kozlowski said via email.

Przemysłlaw Marczewski, a representative for the national Polish Tourism Organisation told CNN Travel on February 25 that "travel to Poland is smooth, and the borders of the Republic of Poland with neighboring countries are not closed."

Marczewski noted that Polish land borders with Ukraine have been open to refugees and that the travel industry is supporting the citizens of Ukraine with temporary accommodation in hotels.

Tourists with near-term plans to visit Poland are advised to book accommodations in advance, "as part of the hotel infrastructure may be earmarked for those in need."

My flight is supposed to be flying over Ukrainian airspace. Will it be rerouted?

This image from aircraft tracker ADS-B Exchange taken at 11:15am ET on February 24 shows empty airspace over Ukraine and its border with Russia.

If you are flying on a route that would usually cross currently blocked-off airspace, the airline will reroute the flight.

Imagery from February 24 from showed empty airspace over Ukraine and its Russian border.

"For aviation, safety is always the top priority," said Willie Walsh, the director general of the International Air Transport Association airline industry body, in a statement provided to CNN Travel on February 24.

"IATA is helping to facilitate the relevant and timely sharing of information with airlines from government and non-government sources to support airlines as they plan their operations around airspace closures in Ukraine and parts of Russia."

Can I still travel to Russia?

Russian airspace on the border with Ukraine is closed to civilian flights. There are also some restrictions on domestic flights within Russia.

The UK has banned civilian Russian aircraft from its airspace and above its territorial sea from February 24 until May 23. Russian airline Aeroflot usually operates direct flights between Moscow and London-Heathrow and Gatwick, according to its website.

In response, on February 25 Russia's Federal Agency for Air Transport, Rosaviatsia, imposed a ban on UK registered flights, as well as aircraft owned, leased or operated by a person associated with the UK, from transiting through Russian airspace.

Polish Prime Minister Mateusz Morawiecki said on February 25 that he is drawing up legislation that will lead "to the closure of airspace for Russian airlines."

The transport minister for the Czech Republic, Martin Kupka, said the country will stop operations of all Russian carriers in its territory. "As of midnight today, we are stopping the operation of all Russian air carriers on Czech territory," Kupka said on Twitter on February 25.

LOT Polish Airlines has suspended flights to Moscow and St. Petersburg. "For the transit flights there will be alternative flight routes planned," the airline said in a statement to CNN Travel.

The US State Department issued a Level 4: Do Not Travel advisory for Russia in January citing "ongoing tension along the border with Ukraine, the potential for harassment against US citizens, the embassy's limited ability to assist US citizens in Russia," as well as Covid-19 and other factors.

The United Kingdom's advice to its citizens as of February 25 was more specific, advising against all but essential travel to certain Russian regions on the Ukraine border. The UK government also details information on increased restrictions and disruptions to domestic Russian flights, as well as warnings of escalated police presence and ID checks.

"The bulk of our Russia travelers seem to be taking a wait-and-see approach right now, but, of course, this might change based on how events unfold," travel agent Kozlowski told CNN Travel via email on February 24.

Meanwhile, popular travel author Rick Steves, who organizes tours, announced Thursday he is canceling tours in Russia for the remainder of the year.

"Our mission at (Rick Steves' Europe) is to help Americans understand the world through travel," Steves Tweeted. "But when we bring travelers to Russia, we also bring their dollars -- dollars that would support Putin's aggression. We have now canceled all 2022 tours to Russia."

How long will travel be affected?

The situation in Ukraine is fast-moving. It is unclear how long airspace over Ukraine, Moldova, Belarus or Russia will be impacted.

According to the UK government's travel advisory, restrictions on domestic flights in Russia are currently set to be in place through March 2.