I got my 400 5.6 today
I needed it for this.
This was with a 200. resized from 1500 of the original 3300 pixels , so it's pretty heavily cropped.
Thought it was a keeper though , noticed that all four engines have condensation in them , and the jet blast from the far right engine looks pretty good (I thought)
Not much chance of chance of blue sky AND condensation I think.
I thought I had bored myself with aircraft pics , but then I realised I had no condensation pics , but lots of blue sky, so now I look out for bad weather 

