Ans: Let’s assume the airport can accommodate 10 planes at once and handle 5 runways.
Average length of runway = 2000m
Width of runway = 50 m
The total area of runway is 2000*50*5 = 500000 sq.m
Length of average plane is assumed as 50m and its wingspan is 40 m.
Total area of 10 planes = 20000+500000 = 520000 sq.m
Now somes assumptions, total area occupied by the building is equal to the area of runways and planes i.e 520000 sq.m
Total area of airport = 104000 sq.m.
There is a lot of empty space on an airport so we assume 40% of the total hence the final area is = 104000/0.6 = 1700000 sq.m.
You can think of different methods to calculate the same, this is just one of the quick way ti estimate the area of an airport