Mental patients in a plane

Johnny was placed in a mental institution. It has been 2 months already.The institution decided to buy another location to accommodate more oftheir patients as it was overcrowded by then, so the institutionmanagement decided that they have to take the patients to the new institution by plane because it's much quicker, so they took all thepatients to plane together along with Johnny of course.

So while in the flight the (Mental) patients were very excited by now, singing and dancing in the plane and the sounds were disturbing, when one of the nurses sent Johnny to keep them quiet at the back.

Johnny went and after a few minutes came back smiling and it was all quiet at the back. The nurses wondered what Johnny had done to keep them quiet, so they asked Johnny what had he done to keep them quiet?

Johnny said with a smile in his face:

"I TOLD THEM TO GO PLAY OUTSIDE."