Planes are designed to not crash in the first place. They are not necessarily designed to survive a crash like a car.
But since you asked the question... there are some safety features implemented to make crashes more survivable:
Airbags (newer feature on light aircraft)
Seatbelts and harnesses
Fire resistent fabrics and carpeting
Fire extinguishers
Fuel additives to reduce spontaneous combustion
Crash attenuating seats
Parachutes for the entire aircraft (such as on a Cirrus)
A big one is proper licensing and aircrew training
There are many many safety standards that an aircraft must meet in order for certification. The purpose of accident investigations is to see how we can improve aviation safety. Aviation is much safer than driving.