My frustration with this thread is that this isn't important. If you are interested in planing - get some kind of bike that might do it and see if you like it. If not, ride what you got.

This isn't all a conspiracy to deprive pros of a necessary advantage. It probably isn't worth giving up aerodynamics just to get "proper" frame flex.

The only reason I participate in these discussions is that it is interesting to me how fervently people want to deny that it is even possible that the flex of a springy bike could have a positive upside. I assume the same people who are so against this possibility had similar feelings about riding tires under 115psi - until the flipped on that. Because it is pretty much the same thing: Sometimes not-so-rigid machinery works really well with humans.