They are quite few and far between. Best time - possibly a non-smoggy day to start off with.. Places on the terminal get a view over the fence into some of the smaller planes (MU 752/MD-80's) but if it's smoggy, the view isn't that surprising-this thick yellow "soup" hangs right in front of your face. Nothing (that I saw) can be seen from inside the landside area of the terminal. Others might have a better idea of where good spots are around the airport.. But I only had an hour or so.