Hmm, you need to think these things through a little more . . .
The reason a plane goes forward very fast is that the engines stuck under the wing pull air in the front and push it out very fast at the back.
So, the air behind a plane is going away from the plane, not following it.
I guess your idea might work for two planes which wanted to fly in opposite directions and where one of them had a big sail on top of it, or for two planes going the same direction where the one in front was about the size of a few double deckers stuck together sideways. I wouldn't remortgage the house on those ones though.
z