A few years ago I flew from MAN to AMS with KLM. The weather was threatening but still dry.
Before we took off the pilot came on the PA as normal with the usual information and added that we might have a few bumps as we climbed due to a thunderstorm nearby. Sure enough, as we climbed there was an almighty bang and a flash from the opposite side of the aircraft (accompanied by a few screams from other pax). Things soon calmed down and the flight settled into normality again once we reached cruising height. I had a window seat on the wing and casually glanced across to the other wing. Looked at it, looked at my side's wing and looked back at the opposite wing. The winglet on the other side was no longer attached....it had gone AWOL. I sat there thinking, "someone under the climb out route from MAN had received a new garden ornament" (hoping no-one had been attacked by it).
Landed perfectly fine at AMS, everyone got off the aircraft without further issues.
The aircraft on the other hand was towed from the gate, last seen heading for the hangar....and a new winglet.