This is NOT inevitable -and even if it was, this is not the time to start. Neither is it a logical follow on to our swingeing road fuel taxes. Even for that, most countries in the world tax fuel at very much lower rates than those you quote, phd. And so far, no country has claimed the right to levy duty on fuel used on the high seas or international airspace.
If this is implemented in the EU as opposed to a worldwide basis, it will result in a sharply uphill playing field for all EU airlines as they attempt to compete with those in the rest of the world. There is no question of this being an "environmental tax". It is just another excuse to gouge our industry.