Catcher in the Fly

Designing a reusable rocket costs billions of dollars and takes almost a decade to successfully implement. In the meanwhile, space agencies can do the following. Catch the used first stage on air. If the space rocket that is already in use has restartable engines then the problem simplifies. A large fishnet made of carbon fibers carried by cargo drones would catch the falling rocket on air. For this thing to be possible, the first rocket stage should disengage from the second stage with some fuel in reserve and stop its engines. The remaining fuel should be fired close to the rocket catcher rendezvous and should be shot down before falling on the net. So that the falling rocket would have much less speed and the fiber net don't get burned. This approach would have approximately 5% less payload to orbit penalty. Which is nothing compared to the cost of the rocket stage. The rocket catcher system would deploy heavy duty cargo parachutes as the rocket lands on the net. This lowers the stress on the heavy lifting drones. After the rocket is catched, it would be landed on a sea or land platform. 

If the rocket in question does not have restartable engines, more powerful net carrying engines should be used, such as rocket engines. Rocket engine powered net would catch the falling rocket much higher in the sky and gradually slow down the falling rocket. Then the rest is landing the rocket on the platform.