Rishi Sunak shelled out more than £10,000 to fly by private helicopter to a glitzy Tory dinner in Wales at the weekend.
The multi-millionaire Chancellor paid out of his own pocket for a return flight from Battersea heliport to the Conservative conference in Newtown, Powys.
The revelation will heighten concerns that he is too "out of touch" with ordinary voters to understand the impact of the cost of living crisis.
Mr Sunak and his wife Akshata Murty made the Sunday Times Rich List for the first time this week with their joint £730 million fortune.
The Chancellor suffered a major political blow after it emerged last month that his wife was non-domiciled for tax purposes - meaning she had avoided millions of pounds in UK tax.
Treasury insiders said Mr Sunak, who took part in a Q&A with Tory former leader William Hague ahead of the dinner, travelled by helicopter to save time.
Less fortunate attendees travelling from London would have had to pay £117 for a return train ticket in standard class, or driven the 400-mile round trip by car.
But shadow financial secretary James Murray said: "Flying to and from Wales for dinner speaks volumes about how out of touch this Chancellor is.
"If he's that wasteful with his own money, it's no wonder he treats the public finances as carelessly as he does."
He added: "He should get his feet back on the ground and start paying attention to the problem most families face - soaring bills and rising prices".
A Treasury spokesman said: "The Chancellor looks to minimise the amount of time he spends travelling, so that he can spend as much as time as possible focusing on delivering for the British people".
It came as ministers warned at Cabinet that millions of public sector workers, including nurses, police and teachers, may not get a pay rise this year to avoid "spiralling" inflation.
The PM's official spokesman did not rule out overriding the decision of the independent pay review bodies - which are due to report before summer - if they suggest above-inflation rises.
He added: "Ministers made clear the risk of triggering higher inflation must be part of considerations when deciding pay awards this year.
"I don't want to jump ahead of the independent process. You'll know the Government has the capability to do that in the purely hypothetical sense.
"The point that ministers were emphasising is that a spiralling inflation will do more to damage people's take-home pay than limited pay restraint."
