I think the difference isn't in the distance travelled, although I am sure you found it very inconvenient Demigod_Tyek, but more in the population densities of the related areas vs Iron Maiden fans. Starting in 2012 with the Maiden England World Tour, Iron Maiden has played 42 times in the USA, a total theoretical capacity of 871259 (without including Canadian dates, which are accessible to many Americans). The UK has had a total of 5 concerts, with a capacity of somewhere around 150,000. Given the density of Iron Maiden sales in the UK compared to the USA, I think the USA had a much, much greater access over the past two tours.