Eight FLYABLE planes verses the original FOUR that came in the original RoF. I'd check the RoF website store for clarification though.
I'm sure there will be a sale again where extra planes can be purchased for half price. ALL the planes are available as AI. So flying the Handley bomber is out unless you buy it, but you can fly against it no matter if you own it or not.
If you already have the demo installed (which appears you do) ......
http://riseofflight.com/en/store/demoupgrades