Aviation fuel pays no tax at all, although if it were taxed at the same rate as unleaded petrol, this would raise some £5 billion a year.
I always love statements like this because they are saying that if the cost of aviation fuel were tripled or whatever by tax, exactly the same quantity would be consumed as before ! So they expect no environmental benefit at all, just a tax grab.
The Greens cocked it up similarly with the London Congestion Charge, saying it was to aid the environment but calculating the expected revenue as if the same traffic levels continued as before. As the traffic fell, they are now way below their own budgets for charge income, and having to think about putting public transport fares up to bridge the gap ! Of course if they put the charge for cars up even more cars will be deterred and income fall further.