Allow landings and takeoffs only at designated spots, like major spaceports?

This concept allowed controlled landings (unlike parachutes), and it was 1/5 the weight of fixed wings.

It was the first major effort by the Japanese to allow uncontested landings for the purpose of creating a kill zone inland.

This allowed stalled landings with no ground roll.

As the instrument rules allowed landings in reduced visibility, any boats at the ends of the runway would not be seen by passenger aircraft.

Later, concrete surfaces would allow landings, rain or shine, day or night.

As they were arranged in a form of a triangle, they allowed take-offs and landings in six directions.

Its large runways and the distance between them would allow simultaneous takeoffs and landings.

For production models, a set of landing flaps allowed somewhat more-controlled landings.

The flight deck has 5 helicopter landing spots that allow simultaneous landings or take-offs.