A training exercise involving hundreds of Nato warplanes over European airspace could mean bad news for some holidaymakers this month.
Air Defender 2023 – which began today and runs through until 22 June – has been billed as the biggest air force deployment since the formation of Nato.
The huge multinational manoeuvre – which will look to showcase the alliance's capabilities – will be centred over German airspace and involve 10,000 military personnel and 250 combat aircraft from 25 nations, including the US and UK.
All of the participating Nato allies will be training for air operations under the command of the German air force.
According to the German armed forces website, flight altitudes during Air Defender "will range from 2,500 to 15,000 metres and higher", and "no missions are usually flown below that".
"Refuelling generally takes place at altitudes ranging from 3,000 to 10,000 metres. Jet-fight training flights take place at altitudes of 2,500 or 3,000 metres, depending on the airspace activated."
It added: "In close co-operation with the authorities responsible for air traffic control, the airlines and the civil airports, processes and procedures are currently being optimised to minimise the impact on civil air traffic as far as possible.
"The latest results of the last simulation by Eurocontrol on the impact of Air Defender on civil aviation have shown that no flight cancellations are to be expected, but at most delays."
Lower-level flights are planned over northern Brandenburg, parts of Mecklenburg-Western Pomerania, and the Baltic Sea.
Certain areas of airspace will be reserved for low-level flights for three hours at a time on every day of the exercise, and "sporadic low-level flights" will take place at Baumholder and Grafenwoehr military training areas.
Eurocontrol, the organisation that's responsible for co-ordinating European air traffic, said in a statement: "Eurocontrol have been working upstream for a number of months with the German air force, airlines, DFS and many other air navigation service providers to make sure this major military exercise can take place with the least possible impact on civil air traffic.
"It is possible there will be delays or route extension, comparable to what would take place on a busy summer day.
"We do not anticipate that there will be any need for air operators to make precautionary cancellations in order to accommodate the needs of the exercise."
The North Atlantic Treaty Organisation, known as Nato, is a military alliance made up of nations across Europe and North America.
Formed in the aftermath of the Second World War in 1949, Nato's original goals were to secure peace in Europe, promote co-operation among members and counter the threat posed by what was then the Soviet Union.
A Nato military official said: "Air Defender 2023 is one of the biggest allied air exercises in decades.
"As such it is a key event offering large-scale flying training to participants from 25 nations.
"This is essential to enable interoperability among Nato air forces and the deployment reinforcements from across the Atlantic."
The official went on to say the exercise "showcases the transatlantic link in Nato and bolsters readiness to deter and defend our allies against any threat".
This comes after RAF Typhoon aircraft deployed to Estonia as part of a Nato mission were scrambled to intercept a Russian spy plane and its escorting fighter jet.