Do you think they could literally smell the flak?

[Strike]

I read somewhere a Mustang pilot dipped down over berlin to pursue a german fighter towards the end of the war, he noted he could smell the stench of dead bodies from the devastated city. Can't find the reference, might have actually read it in a book.

I think it's quite obvious that if an aircraft uses ram-air or outside air it would be noteable. As long as the crew keeps their masks on, they should be fed by the oxygen tanks, which, unless someone at the re-fill station is doing a practical joke, should smell like air. If a bomber dropped to lower level, i still believe that the dominant smell would be of aviation gas or fuel. Distinguishing cordite smell from gas/fuel is hard. They don't smell the same at all, but the fuel sure dampens your smelling-sense, at least JP-8 does it :p

My jet once had a small electrical fire and I didn't smell it until after shutdown. Turned out some wires had short-circuited, arcing and caused the isolator to burn, releasing a smoke-puff of foul smelling burnt plastic.