Now I don’t agree with it (in fact, I am strongly opposed to the tax exemption), but the reasoning is that this way you create an ‘even playing field’ for aviators all across the globe. In other words: it’s doesn’t become more attractive to tank in Arab Gulf states, making their airlines out-compete European airlines.
'No-water' hydropower turns England's hills into green and pleasant batteries (www.rechargenews.com)
Why are flights cheaper than trains in Europe? (www.euronews.com)