There should be some additional field which can be filled out or checked after the flight. Like landed, current airport, squak, needs maintenance, something not working, approx gal fuel left, hobbs, tach, flown hours, tie down spot number, ...
So the flight school can see all the airplanes are on the ground, needs to order fuel for the next flight etc.
Especially usefull if nobody is in the office any more when you come back from a flight.

It should be possible for the flight school to set the rights so comments can be changed any time (and for example not only up to 24h before the flight) for the student. So it's possible to give a feedback after e. g. a solo flight.