This is interesting...

[winslow33]

I once read where neither the Allies nor the Axis forces used poison gas during WWII. I guess they were wrong.....

[Hurricane]

I dont recall anything about gas being used. The pictures don't look like they're WW2, maybe a bit earlier, testing or something?
I'm sure one of the experts will be able to give you more details about the type of aircraft (can't think of its name right now) and context.

[Moses03]

The aircraft is a Dornier Do 23G.

From Green's Warplanes of the Third Reich:

"Other Do 23Gs were passed on to the Luftwaffe branch of the Forestry Service, the Fliegerforstschutz, for aerial spraying and other tasks."

This started in summer 1936 when the 23s were relegated to second line duty according to Green. Nothing nefarious going on here as James mentioned. Interesting pics though.

http://i41.tinypic.com/5mjyuw.jpg

[hewman100]

The only spraying I can think of during WW2 was in Burma, when Hurricanes were fitted with equipment to use DDT on the mosquitoes.

[lefty]

Found another pic