(CNN) — Russia's invasion of Ukraine has spurred travel interruptions across the globe.
In response to the EU ban, the Russian Civil Aviation Authority announced on Monday that it has closed off its airspace to the carriers of 36 countries. The list also includes the United Kingdom and Canada, which have both banned Russian aircraft.
Switzerland has also closed its airspace to Russia, with Russia responding with a ban on aircraft from Switzerland.
Lask week, Ukraine's airspace closed in the wake of the Russian invasion. Ukraine's neighbor Moldova also closed its airspace, as did part of Belarus.
The US government's Federal Aviation Administration had told US pilots last week to avoid "the entire country of Ukraine, the entire country of Belarus and a western portion of Russia."
The European Union Aviation Safety Agency, known as EASA, has warned of a "high risk" to civilian aircraft flying near the Ukrainian border. 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 and Russia.
Cruise lines have altered itineraries that included Russian ports of call.
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.
"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."
Hungary tourism officials say the country is open to visitors.
"Hungary remains a safe country, and life continues as normal here," the Hungarian Tourism Agency said in a statement to CNN Travel. "The Hungarian Government is doing its utmost to avoid involvement in the war, and to preserve the safety of both the residents of Hungary and the tourists who visit."
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.
"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?
Countries including the UK and US have issued warnings on travel to Russia due to the current conflict.
The US State Department issued a Level 4: Do Not Travel advisory for Russia in January and updated it on February 28 citing the "unprovoked and unjustified attack by Russian military forces in Ukraine, the potential for harassment against US citizens by Russian government security officials, the embassy's limited ability to assist US citizens in Russia," as well as Covid-19 and other factors. Canadian citizens are advised to avoid non-essential travel to Russia due to the conflict, and avoid all travel within 50 kilometers of the Ukraine border.
Current flight and airspace restrictions also make travel to and from Russia difficult.
EU airspace is closed to Russian aircraft, as is US, UK, Canadian and Swiss airspace.
"These aircraft will no more be able to land in, take off or overfly the territory of the European Union. This will apply to any plane", European Commission President Ursula von der Leyen said on February 28 about the EU ban on Russian airspace.
In response, Russian airspace is closed to at least 36 countries.
Delta Air Lines has suspended its codeshare with Russian national airline Aeroflot.
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."
Norwegian Cruise Line says that it will alter cruise itineraries that include St. Petersburg, Russia, due to the "escalated situation between Russia and Ukraine," according to a statement from the company.
A spokesperson for Norwegian said the company is working to confirm replacement ports and will inform impacted travelers.
Carnival Corporation, with more than a half dozen cruise brands, Tweeted over the weekend that its brands would be modifying itineraries in response to the situation in Ukraine. "We stand for peace," the company said.
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.
Top image: Passengers are seen at Sheremetyevo International Airport outside Moscow, Russia. Alexey Maishev / Sputnik via AP