32 fps looking at the entire airport isn't a good number? Wow, last time I checked 32 fps was pretty smooth, must be something wrong with your perception of smoothness.
He commented on my screenshot, saying that 32 fps is not much for a default airplane, however my screenshot displays 36.9 fps, not 32...
And, in any case, he said "I don't get any issues with your LAX scenery, I have 26-30fps in the VC there" so, he surely must know that 26-30 fps is very good on a large airport.
But the issue discussed here is the reported large fps drop when looking at the control tower. My screenshot simply proved there's no such drop. Yes, of course, I have more than 45-50 when looking at the sea, but that should be quite obvious. What counts is that it remains very good ( 37 fps on my system is VERY good) even in the worse case scenario.
Of course, if he gets 30 fps too with a default airplane, and 15 with a too memory hungry airplane, we are not discussing scenery performance anymore here, but airplane performances.
A possible cause might be: that airplane is taking a lot of VRAM so, in combination with the scenery, the amount of VRAM used is too much and the card is start to swap memory between main RAM, and that will have a large impact on fps. Obviously not a problem of the scenery, it's exactly the same issue of OOMs: using many things in combination, it's not anybody's "fault" if there are problems, and it will be necessary to start lower settings, not use HD textures, use less stuff together, use DX10, etc.