Ryanair boss Michael O'Leary has hit out at proposals for a fast rail link between Heathrow and Gatwick airports.
The proposed link, which would follow the route of the M25 and mostly travel underground, would enable an airport hub dubbed "Heathwick" to be created.
The Department for Transport said at the weekend the plan, set to cost a reported £5 billion, was under consideration.
But speaking at a press conference in central London, Mr O'Leary, chief executive of the Irish airline, said: "This Government has no policy on aviation whatsoever.
"They have no particular expertise in tunnelling. The last one they did was the Eurotunnel, which went bankrupt even before it opened."
Mr O'Leary, who was speaking at the launch of Ryanair's new Cash Passport scheme offering passengers savings on their flights, also blasted London Mayor Boris Johnson's idea for a new airport in the Thames estuary.
He said: "What you really need to do is build three additional runways: one at Gatwick, one at Stansted and one at Heathrow, which you could actually do for about £150 million to £200 million in each of the three airports, and you would finally have addressed the major problem here in the UK, which is the massive undercapacity of airports in the South East.
"But wasting multi-billions building a bloody airport in the middle of the marshes somewhere where you then have got to build motorways to it, rail transport links - it's mad."
Yesterday Mr Johnson wrote in the Daily Telegraph: "I stick to my view that we need to think big, and the place where you could create a 24-hour hub airport that would leave our competitors standing and with the minimum disbenefits to human beings is in the Thames Estuary.
"Such an airport would be an astonishing motor for growth in an area that has been left behind for too long, and it would entrench London's lead, for the next 50 years, as the economic powerhouse of Europe."
Commenting on the Heathrow-Gatwick link plan at the weekend the Department for Transport said it was not Government policy but was being considered.
He said: "The Government is committed to developing a new policy framework for aviation which supports economic growth while addressing the environmental impacts of flying. We plan to publish a draft aviation policy for consultation in the spring.
"As part of our work on this we are seeking views on the key issues which need to be addressed, including the importance of a UK hub airport and whether it might be possible to create a 'virtual hub' by improving connectivity between existing airports.
"This proposal will form a useful contribution to the debate and will be considered alongside all other responses."