I know that on RC cars we have a failsafe incase the car goes out of range or loses power. what happens if that happens in a plane? it just crashes? is there anything you can put in it to prevent that?

nope once its byegone its byegone (or momentarily gone if you u run for the thing).
actually, the plane usually is out of range when its so far away u dont see i anymore, so u can decide whether to hop on ur and start chasing it down or report a fugitive model airplane has crashed and u wnna know where the wreckage is.
in case its a battery fail, there are failsafe systems that include a spare 270mAh+ battery with an extra switch harness a loBat warning light(VERY Bright un) a scarily loud beeping alrm for loBat and/or crashed and lost plane that activates a minute after there havent been any input to the Rx(this is also useful when u forget to turn off the receiver.

whats all that stuff called?

Electro Dynamics makes one. They are out of Michigan and have good electronic accessories.

Dan,
Actually, if you want to go to the additional expense of buying PCM radio equipment you can have a failsafe of sorts. You can program the Rx to hold preset points on the servos such as, slight right rudder, ailerons and elevator at neutral, low throttle. That way the plane will make wide circles and descend.

Funny though, the majority of people who have PCM equipment never use the feature.
Dennis-

I dont know how much those cost, but by the sounds of it....they ar too expensive. I cant even by a plane until a year or two

With futaba equipment, a 7 channel PPM receiver is $60 and an 8 channel PCM receiver is $100