SAS: https://www.thelocal.no/20180529/smo...g-in-amsterdam
Lufty: https://www.thelocal.de/20161019/luf...enters-cockpit
Icelandair: https://www.icelandreview.com/news/s...landair-plane/

Bottom line: when Googling you can find such situations with every single airline. Aeroplanes - just like any other piece of mechanical equipment - does break down at times. The good thing is that planes are actually designed to withstand such problems and have safety workarounds for about any possible breakdown. Whether it is smoke in the cockpit (which in 99.9% of cases is not a big emergency - but rather requires a landing out of precaution to check it out) or perhaps a complete engine to fail: aeroplanes can fly on fine for dozens of minutes afterwards and touch down safely. It is nothing to worry about and such news are most often always blown out of proportion, instead of the word 'emergency landing' the term 'precautionary landing' is a much better fit in most cases. Needless to say, in all these stories the planes just landed perfectly normally and there was never any panic on board - as a passenger you would probably not even notice a thing of it!

Fact is that flying is much, much safer than any other form of transport - including taking a bus or driving yourself. Rationally, there is of course nothing to be afraid of. Unfortunately, the human brain does not work like this and your fear of flying is for sure nothing to be ashamed off, many people have similar thoughts - some so bad that they really are hesitant of flying, while others might still have secretly some bad feeling each time they set foot on a plane. Given that driving (which is so much more dangerous) is still such an everyday thing for most, and flying is still let's say rather unique (also as it involves going up in the sky, battling gravity and other such things which dwarf common human feelings) it is only understandable that the mind perceives it differently - whether it is justified or not.

Given that Condor - just like Lufthansa or the other airlines you mentioned - has a generally good historical track record and has all the permits it needs to operate flights within the EU (so no possible dodgy maintenance or other such quirks) I really wouldn't hesitate flying it myself. My worries would only start at airlines which are banned to operate in the EU for example (although arguably many of them are still safer than driving a car!).