Inflation

More than 80p a litre for what cost just over 50p a year ago.

"It's only aviation fuel", he said.

I imagined a flying visit to Venice for my parents, in their own accommodation.

We could claim the VAT back then, I am sure, as UK airlines don't pay tax on fuel. Funny that Mr Rees-Mogg didn't mention this when asked about Brexit benefits (the EU has decided to start charging excise on fuel for intra-EU flights to reflect climate costs).
https://www.transportenvironment.org/discover/what-the-eu-climate-law-means-for-jet-fuels-tax-exemption/

Someone with deep pockets is needed to reduce the carbon cost of running this house, I'm afraid.