You realise there's probably millions of foreign workers in various countries around the world who move abroad to support their families and flying is the only way for them to see their families.
For most people flying is anything but a luxury. Most people are flying in economy for business reasons that they have to do if they want to earn an income.
Companies engage in huge amounts of wasteful travel.
Business passengers are the majority of airline profits. Airlines will gladly fly economy class half empty as long as the business class seats are sold out. Hell, some airlines have the business and premium economy cabin taking up over half the plane's available square footage.
Economy class passengers are most negativity affected by the tax, yet this is unlikely to change airline behavior.
Ideally in the long term everything would be taxed precisely according to its' externalities.
In the short term it makes sense to have a progressive system that more heavily taxes luxuries so that the poor don't get thrown under the bus (read: throw you under the bus).