How many people are able (can afford to) to fly on planes?

[o]

here in the uk where i live, and other places like usa, europe etc. we take for granted air-travel; but what percentage of the world's population can do that? i'd imagine that most people on earth simply cannot afford it. if you know the answer, or better still can provide a link to research or statistics, i'd be very grateful

[Hymie]

Part 1:-

Sadly, our lamentable education system does not teach lateral thinking required to answer such questions (or even to attempt them). Many would dismiss such a question, since there can be no absolute answer. This misses the value of such questions, where the answer cannot be learnt, parrot fashion, from a book.

So here is my answer � or at least a method to determine an answer (I trust you will cite me in your submitted homework).
[I should also point out that the internet is a great source of information � otherwise researching the basic information required to estimate an answer would take a considerable time/effort.]

First, you need to consider the income per year that will enable someone to afford to take a flight. I am arbitrarily going to say that is US$10,000. Now you might say that there is no way that someone in the UK with such an income could afford to fly. But in many parts of the world, having an annual income of this amount would put you among the top earners within your nation.

You can select your own annual income level � you could even make the calculations for a range of income levels to see how it effects the answer.

[Hymie]

Part 2:-

On Wikipedia, search �list of countries by GDP per capita�. This is a crude, but useful (over) estimate of income per person. Take a note of all those countries having a GDP per capita equal to or greater than your chosen annual income level.

Now search Wikipedia �list of countries by population�. From the % column, add all the noted countries to find your total percentage.

You should comprehend the limitations/errors of my method. Take the UK, based on my method, 100% of the population can afford to fly, and 100% of the Chinese population cannot afford to fly. Clearly neither statement is correct � however such anomalies will be evened out to some extent by those countries meeting the GDP per capita criteria, having 100% of their population qualifying as being able to afford to fly (versus those not qualifying, excluding 100% of their population). You should mention these and other failings, in you homework, for extra marks.

You could even use lateral thinking to improve on what is admittedly a fairly crude method of estimating an answer.