1. Number of inhabitants in the country
2. Segment them according to age
3. Differentiate the segments based on their defining characteristics, e.g. people beween 0-10 typically do not fly, between 30-40 fly let's say 5 times a year on average, i.e. 10 flights per person
4. Add them up and devide by number of days?
5. Define how many people fit into a plane
6. Define uage capacity
7. Define non-flight hours of airports, e.g. 0-6am