Flying is an exceptionally easy target for this sort of thing, unfortunately. Impacts a small percentage of the population, Hunt can badge it as hitting the wealthy and also hitting a polluting industry.

Meanwhile in reality, the amount raised will be chicken feed in the context of funding a tax 'cut' for a direct tax like NI. It's all rumours, but I wouldn't be surprised to see a lot of things like this put up so the Chancellor can grab himself a headline.