I don't think this is true. PT-Boats already have a model for movement on water.
Radar and scout planes have nothing to do with each other. Our 25 mile radius radar doesn't change what limited uses a scout plane would have.
I was thinking on the PT boat idea for awhile when the last PBY wish came forth.
While I don't know the technical 'stuff' behind what makes the planes fly in-game and the PT boats "float", I figure since those components of travel are there, perhaps they can be combined together in the form of the PBY.
As for radar and scouts, that was more of an opinion (isn't everything?) instead of 'stated fact'. It was based off of the 'normal' player actions. For example with the FI marker plane. Why would you fly that and mark a tank when you can take off in a ju87 and kill them (or il2) or go an even easier route with the a20 or heavy bomber (rumored lancstukas).
I still think it should be added to the game and available at ports, I think at the very least it would be an interesting addition .