Most weekends we see a 'row' of 5 or 7 old looking airplanes flying in some sort of formation. Are they airforce or private. They are generally boxy in appearance and look grey (although it is obviously hard to tell due to their distance). Normally they are an odd number which always strikes me as odd.
Any answers from the aeronautical members - of which I know there are many.

Ju-87's fly out of the Dübendorf flugplatz every Saturday around 3.
Usually only 1 though.
They're big 3 engined things, that Hitler always got out of.

I think I've noticed a formation that includes a DC-3 from time-to time as well. Occasionally, they'll fly on weekdays as well.

It'd be interesting to see how much corrosion is in these aircraft. Other planes of the era had much of the construction out of dissimilar metals.

http://www.airforcecenter.ch/navy/mainnav.php?langy=d

DC