If you are into saving weight and money, the best battery I have used for Rx is a 700 mAh LiFe battery. The LiFe battery does not self-discharge and a 700 mAh will last me several flights and charge fairly quick. Only thing is you need a charger that can charge LiFe batteries.

Battery: https://hobbyking.com/en_us/zippy-fl...iver-pack.html

Charger: https://www.towerhobbies.com/cgi-bin...&I=LXZWP0&P=ML (You can take it to the field with you and use it with a 12V battery to recharge your Rx battery if you need to, but I have never needed to do that)

Just make sure that your servos are not so old that they can't take the 6.6 Volts of the LiFe batteries. All my servos can handle it and they go back over 10 years.

Stay away from Lipo and NiCD batteries. Lipos have to be removed from the plane to recharge them (and they are still hazardous) and NiCD's are bad for the environment.