Boris Johnson has been criticised after using a private jet to fly from Doncaster to Darlington - a journey that takes less than an hour by train.
The prime minister took the plane as he embarked on a tour of marginal constituencies in the north east three days before the general election.
Doncaster and Darlington are connected by a direct train route that takes 53 minutes, but the prime minister instead opted for a 25-minute flight.
Opposition parties criticised the "unnecessary and environmentally damaging" journey, while environmental groups called it "absurb and unacceptable".
Mr Johnson has often talked up his party's green credentials and last month claimed that there was "nothing more conservative than protecting our environment".
Short flights are one of the most environmentally damaging forms of transport.
Mr Johnson and his team, plus journalists travelling with the prime minister, were the only passengers on the flight, which those on board said was only two-thirds full.
The plane was operated by Danish charter company Alsie Express, which says it allows customers to "make the most of your aircraft and your time".
It guarantees "time, comfort, [and] hassle-free travel without a moment wasted" and promises passengers that it will make sure "that your favourite drink is perfectly chilled".
Mr Johnson was expected to use the plane for a second flight, from the north east to the Midlands, later in the day.
Announcing his party's environmental policies last month, Mr Johnson said: “There is nothing more conservative than protecting our environment and these measures sit alongside our world-leading commitment to net zero greenhouse gas emissions by 2050."
The party's manifesto promises that the Tories will "lead the global fight against climate change", and includes pledges to "support clean transport to ensure clean air" and "crack down on the waste and carelessness that destroys our natural environment".
Opposition parties and environmental groups criticised Mr Johnson's decision to take the short flight.
Andy McDonald, Labour's shadow transport secretary, told The Independent: "How can Boris Johnson say he is committed to bringing down emissions when he's prepared to take unnecessary and environmentally damaging flights?
"Boris Johnson is living proof that the majority of flights are taken by the privileged few, while the rest of us pay the price of global heating.
"Under a Labour government we'll make sure that our trains and buses are properly invested in, so that Boris Johnson can make more environmentally friendly decisions in the future."
Greenpeace UK’s chief scientist, Doug Parr, said: “Boris Johnson’s manifesto came second bottom in our climate and nature ranking, and now he’s turbocharging his carbon footprint during an election campaign where the climate emergency is one of the top concerns for voters.
“It’s absurd and unacceptable for anyone to take a flight for a journey that could be done less than an hour by train, not least the prime minister, who should be leading by example. It makes his lack of ambition for tackling the issue glaringly obvious.”
Aaron Kiely, a climate campaigner at Friends of the Earth, said: “Saving half an hour of travel time has resulted in a journey that’s far worse for the planet. It’s impossible to see what benefit could come from flying over such a short distance rather than using a train, or even campaign bus. Nobody, including the prime minister, can get away from the fact that fewer planes in the sky will help to fix the climate crisis.”
Conservative officials said the decision to fly had been taken because of the prime minister's tight schedule.