Model Aviation
Here we will touch on all forms of model aviation. follow the Links to the various sections of interest 
Model Airplanes have changed alot in the last 20 years. From basic balsa and light ply kits to foam and fiberglass electrics and even turbine engine Jets. When I started modeling some 43 years ago a quarter scale plane was considered huge, and engines averaged .60 cubic inces (10cc) Now 1/3 to 1/2 scale is normal and engines go to 250cc plus and 2, 4,6 even 9 cylinder radials. Not to mention electric. 
Helicopters also have changed dramaticly over the last 40 some odd years. Starting as fixed pitch with only the throttle and the speed of the head to regulate hieght they where slow to react and difficult to fly. No gyros to stabilize and mechanics that where large and cumbersome not to mention expensive. Now you have fully collective flybarless heads. full stabilization and again electrics that out perform the internal combustion counterparts. 
One of the latest of the radio controlled model groups to come on the market and also the most controversial. The Drone ot Quad-copter is unique and probably the easiest to fly. Even the smallest and cheapest of the group comes with full 3 axis stabilization, and even cameras. Larger more sophisticated versions can have GPS location and return home features and programable flight way points.  
Model Electronics have come a long way since the 60s and 70s. Servos are digital and programable, Electronic speed controls also are programable, Three axis stabilization systems allow us to fly in adverse conditions even with small light aircraft. GPS, self landing, redundant power systems, and aviation lighting systems are just a few of the available gadgets available. 
And last but defiantly not least our radio systems .Back in the day we had 27Mhz AM and it was ok but sketchy, then we acquired 72Mhz with a few more frequencies. Today we enjoy 2.4Ghz frequency hopping systems with built in computers that can save 30, 40 50 models and more in memory. Open source radios we can add programing to ourselves and multi protocols so you can fly with multiple brand receivers. Telemetry feeds from your receiver can tel you altitude, speed and more.