Greenpeace has attacked Boris Johnson's plans to slash taxes on short flights within the UK - despite pledging to help the environment.
A review today reveals Air Passenger Duty could be cut on domestic flights under plans to improve connectivity within the United Kingdom.
Boris Johnson said he wanted to "build back better" after the coronavirus crisis in a way that brings "every corner of the UK closer together".
It comes after the stricken aviation industry has asked for more government support to preserve thousands of jobs during the pandemic. Aviation bodies also complain APD is levied twice on domestic flights - on both departure and arrival.
But Dr Doug Parr, chief scientist for Greenpeace UK, said: "After the fuel duty freeze and rail fare rises, cutting duty on domestic flights would continue our nonsensical trend of the higher the carbon, the lower the tax.
"Next they will tell us we need airport expansion and new runways to accommodate all the aviation demand that has emerged.
"The government needs to face up to the unavoidable reality that the aviation industry has to be smaller than it was before the pandemic."
Sarah Olney, Lib Dem transport spokeswoman, added: "Britain will be laughed at on the world stage if we decide to hike rail fares then cut the cost of UK air travel in the same month.
"At a time when other countries are encouraging more people to take trains, Britain’s strategy will be the complete opposite. We will be the odd one out at our very own COP26 summit."
The Transport Salaried Staffs Association (TSSA) said that cutting domestic flight duty "flies in the face of the Government's climate commitments".
General secretary Manuel Cortes urged the Government to invest in "truly green public transport", such as rail, which is the "most effective intercity connection taking people to the heart of our towns and cities".
Transport Secretary Grant Shapps today defended the plan, insisting Air Passenger Duty "was never designed as a carbon tax". He insisted other measures would tackle the climate crisis.
The PM will launch a consultation this spring on reforming air passenger duty - a tax on passenger flights from UK airports - in a bid to improve transport connecting all four nations.
An interim report by Network Rail boss Sir Peter Hendy, who is conducting a review of union connectivity, was published assessing ways transport can better connect all parts of the UK.
The Government will also commit £20 million to develop plans for upgraded rail, road, sea and air links - and explore new requirements to offset emissions and decarbonise aviation.
The money will be spent on exploring the development of projects including improved rail connectivity between the north coast of Wales and England; upgrading the A75 between Gretna, Dumfries and Stranraer; faster rail links from England to Scotland and rail improvements in south-east Wales.
The report suggests the "appropriate rate of Air Passenger Duty for journeys not realistic by rail".
Mr Johnson said: "It's now time to build back better in a way which brings every corner of the UK closer together.
"We will harness the incredible power of infrastructure to level up parts of our country that have too long been left off the transport map.
"This pioneering review by Sir Peter Hendy gives us the tools we need to deliver on our ambitions for a UK-wide transport network that encompasses sea, rail, and road - and I also want to cut passenger duty on domestic flights so we can support connectivity across the country."
Writing in The Daily Telegraph, Mr Johnson said the UK had suffered by not having a UK-wide transport strategy, and had instead lost out by leaving it to the EU under its TransEuropean Transport Network.
"The result is that the sinews of pan-UK transport have atrophied, with inadequate connections, needless bottlenecks and endless delays on the vital links between one part of the UK and another," Mr Johnson said.
He added: "It's currently quicker to get a train from Cardiff to Paris than from Cardiff to Edinburgh. With some bypasses, better track and signalling, as Sir Peter believes, we could run services from Glasgow to London in about three hours, and carry more freight too."
