What a question. Of course, it is a good idea.
Sunday is specially good, because you will see Cathay's A340-300, MH B777, SQ B747, in the evening the Air Mauritius A340-300, and not to forget the SR MD-11 and A332 and many others.
I'd suggest you start your day at about 10.00 at the visitors desk. If you want to start earlier, go to the spotting place at the beginning of rwy 14 or 16 to see the birds landing. From the visitor desk, take also a ride on the guided tour with the yellow bus. The highlight is, when he parkes at the crossroad between rwy 10 and 16. The aircraft takes off at some 50-100 m from you away.
After 13.00 or 14.00 (depending on the sun) yiu can visit the Heliport outside the fences. You will have the sun in your back -> better pics.
If you want to see how spotting can be at ZRH, go to:
, which is my homepage.
Any more suggestions or questions?
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