drawing shapes

i would like to use this great app for paragliding as well. it would be very nice if i could draw some circles or other shapes on a map and be able to put some simple notes with them and save this for offline use. i know there are aeronautical maps etc. however way too complex often. i just want to be able to make a simple flightplan for one flightday this way.

I wonder if it is hard to add something like that ?

grtz Carla