Cheap flights from one country to another has been something that has become commonplace over the last 20 years or so. However, future is not looking so bright.
Many of the factors that influence the rise of cheap airline travel seem to be under direct or indirect threats from a number of sources. In Europe, the rise of Brexit and similar National list policy is directly affected the ability of airlines to run more streamlined international systems. Put simply, the costs of flying from one country to another when all countries have the same financial system in operation.
A second factor affecting the cost of the travel is the rise of terrorism. Flights have to be made safe and this costs money. So when security needs to be tightened the costs necessarily rise. Although it is true that the direct threats to airlines or perhaps less than they were back in the days of the 1970s the perceived threat to Western society at large means that airlines to pay tension to security then perhaps ever before.
The third factor affecting airline costs is the environmental cost that needs to be paid. Jet fuel comes from the same place at four dollars and international agreements are beginning to wind down on the free ride that the sector was affectively getting when it came to paying for the environmental damage being done.