Not to difficult and there are many ways to do it. But here is how I did it.
Cheers 

Nice... but for the effort, you could have made a simple rc controlled switch for less than ₹30

Yes i tried to put a cheap 3 way switch...but the servo had to push more and keeps buzzing even after switching...
Its always  getting loaded.,..
So I just got rid of it...
Maybe with a different kind of switch ....

If you are a bit familiar with electronics, this could help..
Costs less than ₹30 to make one.

Gonna make one asap...tnx buddy...
I don't understand the entire circuit..but will figure it out.

Alternatively I was thinking of opening the servo up...and removing its potentiometer and motor and gear ..and basically just using that little small PCB that they have there...and simply replace that servo motor with lights...
But that would mean wrecking a servo worth 200+..

That is very much possible. You may use a micro servo which costs less but still it would cost more than the circuit I had posted. Going the servo way is also not a bad idea... give it a try.

If you want to build seriously Nav lights for RC plane and if you have little knowledge of electronics ,try to build something like this , i have built this more than 20 times for my friends, it cost less than 100/- rupees including LED's.

http://picprojects.org.uk/projects/navlights/index.htm#Schematic

Programming a PIC is bit complicated for newbies. Can you tell a circuit using 555 timer.

Why use a timer 555 when a d-type flip flop does the job...
Why reinvent the wheel?

4013 is easily available at most electronics shop for like ₹10.00