Aviation is currently the sixth biggest source of UK emissions, but by 2040 the CCC reckons it will be the biggest.

In the past the committee has advised government there should be no expansion of UK airports without a clear plan to cut emissions from the sector. The government is expected to announce its support for a new runway at Gatwick on Thursday, so is likely to be relieved the CCC has dropped that recommendation from this latest carbon budget.

But it says the aviation industry will need to pick up the tab for the costs of decarbonising the sector. That is going to require technological innovation – more efficient jets and electric planes – and the increasing use of sustainable aviation fuels (SAF).

SAF is made from plant products or by combining captured CO2 with hydrogen. Just 1% of jet fuel is currently SAF, but the CCC expects that to rise to 17% by 2040.

Any emissions the industry cannot eliminate will need to be offset by what the CCC calls “engineered removals”. That means using technologies to take CO2 out of the atmosphere and store it permanently underground.

All of which is going to be expensive and will drive up ticket prices. The CCC expects those higher prices will slow down the increase in passenger numbers in years to come. However, it still expects a 28% increase in passenger numbers by 2050 – with UK residents taking a total of 402 million flights a year.

It has a warning though. If all that new tech doesn’t cut emissions as much as the industry is expecting, the government may need to impose limits on flight numbers.