Best lens for aerial photography?

What's being shot?
What's the camera platform?
What's the planned altitude?

Again, Thank You for all that good information!!!

A local business development company has asked me for photos of the local airport - plane landing or taking off - so I contacted one of the pilots and he suggested also taking some photos from the air. This is prairie country here, small villages, some lakes, lots of wheat fields etc.
I have not seen the plane, so I have no idea as to windows etc. I think the 5D2 with 24-105, 7D with 70-200 with converters along... just in case, 1D3 with 17-40.
I will take the 100-400 along since I do not know about altitude and because of a funeral, cannot find out today!
Thanks again for your help!

I was asked to take aerial pictures of a friend's farm.....Unfortunately the day we went to do this was very dark/overcast....and it was early spring, so not the best time of the year for tree color either. The pictures still turned out better than I expected them to. Maybe you will fly lower than we did...but I highly recommend the 100-400. The only issue might be room to move around in a small plane if you want to change the lens but with that lens I do not think you will have to. Here are a couple examples, both with the 7D. One using a 70-200 F4 and the other a 10-22 lens. Have fun.

Thank you Andy! Great pictures!

Our landscape here looks about the same as your first image!
The weather forecast looks good and low wind!

Hello,
Here are some images from my day!
I was very happy with the 24-105 - first 2 images
all taken thru the window!
The last one is with the 100-400 - not as many keepers as with the 24-105!
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