At the same time, Citigate has landed a brief to launch an exclusive private members club in London.
The two wins indicate a concerted effort by Citigate to expand its luxury client portfolio as the credit crunch hits less affluent consumers.
Citigate will be launching Jet Republic across Europe, but it will focus on the UK, France, Germany, Switzerland and Russia.
Jet Republic has placed an order worth approximately £830m for 110 Learjet aircraft, each of which seats seven passengers. The airline plans to fly to more than 1,000 airports in Europe.
The first flights in the new aircraft will be available from summer 2009. However, Jet Republic will offer charter aircraft from launch.
Phil Anderson, executive director at Citigate Dewe Rogerson, said: 'Jet Republic aims to be the most desirable private club in the sky and to revolutionise the private jet market.
'In a tough economic climate, the airline can cater for the growing demand for this type of travel among European business people and wealthy consumers.'
Separately, the agency has been brought on board to support the launch of a private members club in London.
Jalouse has been created by Moruf Yoozooph, Roger Michael, Alex Nicholl and Nick Gold, who are also behind famous London nightspots such as Amika and Browns.
The interior of the multimillion-pound club has been designed by award-winning artist Hark Humphreys.
Citigate's brief is to support the launch of the club on 8 October with a gala opening night. The 500 members already signed up include actors, musicians and artists.