The Economist put together insights from Beth Berman, Kieran Healy, and internet commentators to present a story of inequality in the sky:

• Before the creation of economy plus, domestic flights in the US had a two class system. Economy class passengers made up 93% of the passengers but only got 85% of the cabin space.
• This means planes had a Gini index of 8. The higher the Gini index the greater the inequality.
• With the advent of a third class, economy plus, the Gini index approximately doubled to be around 16.
• On transatlantic flights where First Class passengers are increasingly pampered the Gini index shoots up to 25.
• Just as in the real world inequality is rising in the skies. But it still has a ways to go – the Gini index of the US economy is 48.
• If a plane had the same Gini index as the United States then on a typical jet there would be about 8 First Class passengers, making up 3.5% of those onboard but using 35% of the cabin space.

Read about why the rising Gini index actually shows that air travel is becoming more egalitarian, details about the calculations, and more over here.

Source: The Economist