NATO has been heavily bolstering its eastern flank since the turn of the year in response to Russia's military build-up on Ukraine's border and eventual invasion.
The alliance, including the UK, has deployed more troops and equipment to Eastern Europe following the Russian aggression.
But what NATO aircraft is where and how many are on standby as fighting continues to rage on in Ukraine?
According to NATO, about 30 allied surveillance and fighter jets are in the air at any one time along the alliance's eastern flank.
"NATO air forces have bolstered their presence in the eastern part of the Alliance helping to shield NATO against any aggression," said Headquarters Allied Air Command Chief of Staff, Major General Jörg Lebert.
"Several dozen fighter jets are on alert at any time to respond to possible airspace violations and to deter aggression."
What aircraft is being used?
An infographic published by the alliance depicts what aircraft is where across the alliance.
It shows a range of different aircraft being used by member nations as part of NATO's enhanced Vigilance Activities, a mission brought in to protect alliance airspace after Russia's invasion.
According to the graphic, the UK is providing the second-largest number of different aircraft to the area.
F-35 and Typhoon fighters, the electronic surveillance aircraft RC-135W Rivet Joint, Voyager tanker aircraft and P-8A Poseidon submarine hunter aircraft are all deployed.
The US is providing the most aircraft (11) for enhanced Vigilance Activities, including fighters like the F-35 and F-18, the MQ-9 drone and the B-52 bomber.
Fifteen nations are contributing aircraft to the region, including France, Italy, Germany and Turkey.
Watch: Rare access as crews patrol NATO's frontline.
Where are patrols taking place?
The infographic also illustrates where patrols are happening.
Flights are shown to be taking place along areas including Bulgaria's Black Sea coast, Romania, the Baltic Sea and the east of the Baltic States – Estonia, Latvia and Lithuania.
Headquarters, main airbases and carrier groups are also shown and a "recurring" flight from England to Eastern Europe appears to depict deployments of American B-52s from RAF Fairford to the region.
Three carrier groups are depicted operating in the Mediterranean – two Italian and one American – with jets from the US carrier being used in Hungary.
The Dutch air force is operating from Bulgaria, while Spain, Poland, the Czech Republic, France and Belgium all have jets in the Baltics.
American aircraft are also based in Poland and Romania.
The UK took command of NATO's air policing mission in Romania last month, with Royal Air Force Typhoons leading the operation, while RAF F-35Bs landed in Estonia in March to support the air policing mission there.
Watch: UK takes control of NATO's air policing mission in Romania.