task 1
Display the total seat capacity used for each route with the highest total capacity first.
Include the total capacity, the departure point, arrival point and number of flights on the route
task 2 (challenge)
Display the number of seats sold on each flight along with the number of empty seats.
task 3 (easy)
How many bookings were for adults travelling alone?
task 4 (challenge)
what was the departure and arrival point for the flights with the highest capacity.
