Activists out in force across Europe

More than 100 environmental activists wearing white suits stormed into an area where private jets are kept at Amsterdam's Schiphol Airport and stopped several aircraft from departing by sitting in front of their wheels.

The protest was part of a day of demonstrations in and around the airport organised by environmental groups Greenpeace and Extinction Rebellion to protest over greenhouse gas emissions and other pollution caused by the airport and aviation industry.

No delays to commercial flights were reported as of the early afternoon.

"We want fewer flights, more trains and a ban on unnecessary short-haul flights and private jets," said Greenpeace Netherlands campaign leader Dewi Zloch.

The environmental group says Schiphol is the largest source of carbon dioxide emissions in the Netherlands, emitting 12 billion kilograms annually.

Hundreds of other demonstrators in and around the airport's main hall carried signs saying "Restrict Aviation" and "More Trains".

Responding to the protest, Schiphol said it aims to become an emissions-free airport by 2030 and supports targets for the aviation industry to reach net zero emissions by 2050.

Military police tasked with airport security said in a statement they had "made a number of detentions of persons who were on airport property without being allowed".

The Dutch government announced plans in June for a cap on annual passengers at the airport at 440,000, around 11 per cent below 2019 levels, citing air pollution and climate concerns.

Transportation Minister Mark Harbers told parliament last month his office could not control growing private jet traffic, and the government is considering whether to include the issue in its climate policy.

Meanwhile, in Madrid on Saturday, climate activists glued themselves to the frames of two world-famous paintings by Spanish master Francisco de Goya in Madrid's Prado museum on Saturday, the latest in a string of protests targeting artworks across Europe.

A man and a woman attached themselves to Goya's La Maja Vestida (The Clothed Maja) and his La Maja Desnuda (The Naked Maja), and painted "+1.5 C" on the wall between the two works, video footage showed.

Campaign group Futuro Vegetal said its members carried out the protest.

"Last week the UN recognised the impossibility of keeping us below the limit of 1.5 Celsius (agreed at the 2016 Paris climate agreement). We need change now," it wrote on Twitter.

Groups of climate activists have mounted a series of similar protest in recent weeks in the build-up to next week's COP27 climate change conference in Egypt.

Protesters tried to glue themselves to the glass covering Vermeer's Girl with a Pearl Earring in The Hague and others threw soup over Van Gogh's The Sower in Rome and one of his Sunflowers paintings in London. Both of those works were also covered.

The Prado said its paintings had not been damaged, but staff would have to repair the wall between the two works which were created at the turn of the 18th and 19th centuries.

"We condemn the use of the museum as a place to make a political protest of any kind," the gallery added.

Police said two people had been arrested.

Meanwhile, in London, conservationist Hannah Bourne-Taylor - who went viral earlier this year for letting a baby bird nest in her hair for 84 days - has marched across the city naked and painted as a bird in a bid to draw attention to the plight of the dwindling swift population.

with PA