If you fly from Mumbai direct to NewYork (JFK), you will see that the flight takes what seems like a strange route, going a lot north (close to Moscow), before coming down again near Greenland/Iceland.  This site illustrates this very well !

http://www.gcmap.com/mapui?P=BOM-JFK&MS=wls&DU=mi

http://www.gcmap.com/mapui?P=BOM-JFK&MS=wls&MP=a&DU=mi

This is due to curvature of Earth, Map is not able to dipict the shortest path (its of course not a straight line connetcing Mumbai to JFK). We feel that they take a long path but its not the case, due to convex strucure we can see the straight line, had it been a 3D map, we could have understood it better. 

there is another reason ! most of the translantic or international airlines prefer to cruise on surface rather than ocean due to many reasons like in case of emergencies,and ATC centres to keep contacting them and to control them!

The path follows a great circle - i.e the shortest distance
between any two points on the earth's surface. (class 6 level geography)

It is definitely not because the airlines prefer flying over land.

Nobody enjoys the luxury of wasting that amount fuel.

absolutely right.

Everyone knows the "straight path plotted on an azimuthal map looks curved".  This site is great at graphically illustrating it.

ha ha How can we misinterpret Anwar     

a B777 first officer who taught me may be wrong
i will tell him to ask his capt once again!