The skies above Switzerland are crammed full of private jets as billionaires and world leaders attend the annual World Economic Forum in Davos - to discuss climate change among other things.

There is set to be twice as many jets as normal in the airspace as those attending the meeting insist on travelling in style.

Around 1,700 private flights are predicted over the course of the week, a five per cent rise on last year for the 2014 forum - a figure that will surprise many given that global warming is on the agenda and a private jet burns as much fuel in one hour as a car does in a year.

The mountain town of Davos will host the 2015 World Economic Forum, with delegates travelling by jet

A 14-seater Global Express XRS has been hired for around £18,500 (€24,000) return from Paris to Zurich

Around 1,700 private flights are expected to arrive at Davos this week

This Twitter picture from Flightradar24 shows private jets clustered around Switzerland today

A picture from Flightradar24, a website that monitors air traffic in real time, shows private jets clustered around Switzerland on Wednesday.

Zurich airport will handle most of the incoming private jets, but a new landing zone has been opened up via the Duebendorf military base, near Zurich, which has room for 40 private jets and is a one-hour helicopter ride from picturesque Davos.

Zurich airport has been fully booked for some time, with around 60 jets guaranteed space there.

Speaking to MailOnline Travel, CEO of PrivateFly, the global private jet booking service, said: 'We have booked a total of 20 flights to Davos for a variety of clients.

'For one client, we managed to book an empty leg on one of our flights. We already have a client booked to fly back from Zurich on Wednesday evening (January 21).

The plush interior of the Global XRS that will be transporting delegates to the forum

Delegates who are attending the forum are choosing private jets ahead of road transport

Former US Vice President Al Gore (left) and Live Earth founder Kevin Wall (right) listen to US singer Pharrell Williams during a session of the World Economic Forum on Wednesday

'The Citation XL aircraft needed to reposition back from London to Zurich the following morning, so another client flying in to Davos on day two was able to book the empty leg for just £3,000.

'At the other end of the scale, we have some large body, long range jets flying in, such as a flight from Paris Le Bourget to Zurich in a 14-seater Global Express XRS for around £18,500 (€24,000) return.

'Flights have not sold out - but slot availability is limited for Zurich. Some specific take-off and landing times are no longer available and aircraft parking is limited, so private jets are repositioning in and out from other nearby airports.

'Zurich Airport handles the bulk of business aviation traffic during the forum, with St. Gallen Airport and Samedan St. Moritz Airport also handling an increased number of flights for the event.

'Additionally, the nearby military airport in Dubendorf opens up during this time of year to help ease congestion at Zurich by allowing private aircraft to park there between inbound and outbound flights.'

A customer was able to book a Citation XL flying an otherwise empty leg for just £3,000 from London to Zurich

The interior of the Citation XL which will offer its customers a little bit of luxury on the way to Switzerland

Zurich Airport has room for 60 private jets ahead of the World Economic Forum at Davos

A participant arrives by private helicopter for the World Economic Forum in Davos

St. Gallen-Altenrhein and Engadin are the other airports Davos-bound delegates will have to use if prior booking hasn't been made.

At last year's forum, 500 people travelled by helicopter to the event from Zurich airport, a total of 20 per cent of the entire audience, as trains and cars become the less favoured option.

Natalie Bennett, Green Party leader, said: 'The tally of carbon emissions from this supremely inefficient method of transport is... disturbing. The private jets just highlight the detachment of this gathering from the reality of the lives of struggle of billions around the world.'

Lavish treatment for the world's elite doesn't end when the wheels hit the tarmac.

Last night the state-controlled Russian bank VTB Bank, which has been hit by sanctions imposed by the West over the Ukraine crisis and has since laid off hundreds of workers, threw a huge party at the InterContinental Hotel, according to Bloomberg.

It reported that those attending were served caviar by women wrapped in neon-LED lights and treated to a performance by Grammy-winning guitarist Al Di Meola.

Last year Russian investment bank Troika Dialog, now part of Sberbank, treated guests at the Forum to a display by Russian figure-skating stars.

There are so many parties taking place in Davos this week that London-based LiquidChefs, which has expert cocktail makers for hire, is flying 25 bartenders out to the resort, according to the New York Times.

More than 1,500 business leaders and 40 heads of state or government will attend the January 21-24 meeting of the World Economic Forum (WEF) to network and discuss big themes, from the price of oil to the future of the Internet.

This year they are meeting in the midst of upheaval, with security forces on heightened alert after attacks in Paris, the European Central Bank considering a radical government bond-buying programme and the safe-haven Swiss franc rocketing.

Bennett added: 'Despite the valiant efforts of Oxfam and others to highlight inequality and other social and environmental issues, the pressing issues of economic threat of our still fraud-ridden, out-of-control financial sector, the need to transform our society so that it works for the common good not just the few while operating within the limits of our one planet, are not on the agenda.