In bicycle races one rider will ride closely on the tail of the rider in
front of him so that he will be riding in the "air resistance shadow" of the
front rider.
I know of no reason based on basic physical laws of why this should
impose an extra burden on the front rider except that it seems to violate my
sense that there should be no free lunch.
So my question is: Does the front rider in any way need a greater power
output to maintain the same speed by virtue of having someone drafting
behind him?