What are these strange clouds on the wing and how do they form? [duplicate]

I am having a little trouble figuring out what these strange clouds are. You have a cloud forming off of a fighter jet when it breaks the sound barrier, but this is a different situation.

• @mins Ah, yes. Thanks, A wee typo. I'll edit. Shall we delete the other comments to clean up? – Simon Sep 1 '15 at 9:28
• but this is a different situation. no it's not. Both condensation caused by decompression – Simon Sep 1 '15 at 9:29
• @Federico: Ethan doesn't say that (the link to the duplicate was added after he wrote) – mins Sep 1 '15 at 14:09
• Duplicate questions shouldn't be downvoted just for being duplicates. Being a duplicate doesn't make it a bad question, just a redundant one. – David Richerby Sep 10 '15 at 7:51
• Ethan, what makes you think that breaking the sound "barrier" produces clouds? Condensation cones happen only in subsonic flight. – Peter Kämpf Sep 10 '15 at 8:02