Liz Truss faces a backlash after it emerged she chartered a "luxury" helicopter to travel across the UK for campaign events.
The Foreign Secretary, who looks increasingly likely to be the next Prime Minister, is reported to have travelled from Leeds to London and from the capital to Exeter and back for hustings events.
Labour told The Mirror that the 'tone deaf" Tory contender "cannot be trusted to put the planet first".
Ms Truss has a track record for traveling on expensive private aircraft, with The Mirror last month revealing she spent £500,000 of taxpayers money in three months using private government jets.
Her campaign team said Ms Truss will inevitably use many forms of transport as she "is trying to meet as many members as possible".
This afternoon Kerry McCarthy, Labour's Shadow Minister for Climate Change, said: "If there was any doubt left over Liz Truss ' climate credentials, then her reliance on polluting private helicopters for journeys that could easily be made by train surely confirms that she cannot be trusted to put the planet first.
"This tone-deaf behaviour is hardly surprising from a candidate who supports expensive and dangerous fracking and opposes new solar and onshore wind developments - the cheapest, cleanest, quickest forms of new energy.
"It is clear that Liz Truss is not a candidate who is serious about tackling the climate emergency or the cost-of-living crisis."
The i reports that Ms Truss took at least two helicopter flights in the first fortnight after the leadership race was narrowed down to just her and Rishi Sunak.
A spokesperson from her team said: "Liz is trying to meet as many members as possible over the course of this campaign, as she fights for every vote.
"She will inevitably use many forms of transport as she criss-crosses the country."
Her campaign said any costs requiring to be declared will be done so "in the appropriate way", while transport to and from Tory party hustings have been waived from the campaign budget.
It comes amid questions over the frontrunner's green credentials.
Friends of the Earth has previously voiced scepticism, stating: "Truss’s general economic plan is to focus on reducing taxes, pursuing economic growth, and 'delivering levelling up in a conservative way'.
"The pursuit of tax cuts means that public spending could need to be reduced in other areas in order to pay for it, putting environmental initiatives at risk of the chop.
"Truss’s lack of support for action on climate while in government, as well as her vocal endorsement of climate-wrecking projects such as Heathrow and fracking, don’t paint a hopeful picture for what her government’s climate agenda would look like."
Lib Dem climate change spokeswoman Wera Hobhouse MP told the i: “Sadly this is what we’ve come to expect from Liz Truss’s Conservative Party.
“Needlessly flying around like this makes a complete mockery of her promises on net zero.
“It’s clear that she is not serious on climate change.
“The heatwaves were a stark reminder that climate change is happening but Liz Truss has clearly forgotten this.
“She is flying blind and has failed to address the climate crisis throughout the entire leadership contest.”
