The computer-generated pictures show the ships would match the Houses of Parliament for size and measure 28 London buses laid end-to-end.
The first carrier to be built under the £5.2 billion programme, HMS Queen Elizabeth, is under assembly at Rosyth in Fife and is due to be completed in 2016.
Sections of the HMS Prince of Wales are being built and will be brought to Scotland. The carrier will be finished in 2018.
The ships, which will displace around 65,000 tonnes, will be the Royal Navy's biggest and most powerful warships ever.
They are being built by the Aircraft Carrier Alliance – a partnership of BAE Systems, Babcock, Thales and the Ministry of Defence.
Ian Booth, programme director at the Alliance, said: "These posters depict the Queen Elizabeth Class aircraft carriers in front of the Houses of Parliament and in Portsmouth, where they will be based.
"They're stunning images and show that the UK can expect two really spectacular ships once construction is complete."
Six UK shipyards were involved in building various parts of HMS Queen Elizabeth and around 10,000 people have worked on the projects.
Hundreds of workers at the BAE warship yards of Govan and Scotstoun spent two years building one of the sections of HMS Queens Elizabeth's hull.
When completed, the 8000-tonne segment was as tall as a four-storey tenement and as heavy as a blue whale. It will house sleeping quarters.
Meanwhile, Alistair Darling warned Scotland would face hard choices on defence if it were to become independent as he toured Rosyth shipyard.
The Better Together pro-UK team chairman was at the site yesterday on a "listening tour", which also took in businesses and farmers in Edinburgh and Tranent, in East Lothian.
The former Chancellor of the Exchequer said: "The size of the navy of any country largely depends on its wealth.
"The fact that we have the UK, which is a very large economy and country, means that we have a navy.
"Now, even in these hard times, and the navy is going to be squeezed like other armed forces, we actually would need far more ships than would be built and maintained in Scotland than we ever would if you are a much smaller country like Scotland.
"Ireland has a navy but it's a very small navy. Scotland would need a navy, but nothing like the size of the Royal Navy.
"My argument isn't that Scotland couldn't afford to go it alone. Any country could go it alone, but you would have to make choices."