I tried spot metering a bit, but I found it could hit a very bright part of the plane (a reflection) and underexpose the scene a whole lot. Didn't try center-average or partial though, so I'll try that next time.
As for the KLM, it might be a bit overexposed, and it's not completely sharp. I turned down the exposure 0.5 EV and tweaked the white balance in RAW and it may look a little better now.
I know the 18-200mm is not ideal for shooting planes. I've been considering a longer lens for a while, but I basically haven't found enough reasons to justify a purchase .. yet. Maybe I will now
Thanks for the input. Preeshaidit!