No, we don't say that- certainly not in "multivariable" calculus. In single variable calculus, a commonapplicationof the integral is "area under the graph" but in multivariable calculus a graph does not have an "area" under it- it has a volume.

The "rate of change of flight" doesn't make sense. If you mean the "rate of change of distance flown" then that is the speed. "Reversing" it means going from speed to distance flown. it has nothing at all to do with area.Now

Integral is opposite of derivative

So

I need a practical example in which if we reverse the rate of change we get area?

for eg

iF plane is flying and if we take rate of change of flight then how to reverse it and get area?

I am not getting it!

PLEASE HELP.

Again, finding "area under a graph" or "volume" are specificapplicationsof the anti-derivative. You cannot just assert thateveryapplication of an anti-derivative must give an "area". I recommend that you go back and review the basic concepts of differentiation and integration.