The vehicle or flight batteries used in today’s Electric RC planes multi rotors, cars and trucks are almost exclusively Lipoly or Li po batteries. Here is an interesting article on the chemical makeup and differences of the Lithium Ion Polymer we use vs Lithium Ion Phosphate which are used in the full scale electric vehicle industry.
Many people convert their Remote Transmitters to use these also. However I find it easier to use 2200 MAH MiMh AA rechargeable batteries. You can find these at harbor freight and many other big box stores on the cheap. They can be recharged 1000 times before needing to be replaced and are worry free.
If you stick with this hobby you’ll find you have so many Lipo’s you’ll need multiple chargers or special parallel charging adapters to charge them all up before going to the out to the field.
One of the most interesting things I learned was that there have been since around 2008 some full scale ultralight builders using our hobby batteries to power electric full scale ultralight aircraft. Based on estimates they are using the equivalent to about fifty 5000MAH packs to power full scale single person aircraft.