You might do some research online. I'm sure this type of thing has been done with unmanned (i.e. RC) aircraft and balloons before. Reading about it may give you some ideas and directions to go in. Do you have a university in your area with an environmental or atmospheric science department? If so, someone there may be willing to give you some information.

If that project doesn't work out, you could always devise some sort of aerodynamic test project that would utilize your plane. Even something as simple as determining which prop pitches, blade shapes, etc. give bets performance is science if you record and analyze the results.

It know you say you're looking for an excuse to fly at school but it could really be more than that. Science is fun. Testing, analyzing and proving/disproving things is a very useful skill. If you can combine it with your hobby, even better.