Budget airlines go bust left, right and center. Berlin Air is one of them. Forget the "cheap" flights (unless you are a gambler) and go with the established airlines. British Airways, Air France, Lufthansa etc, they would all get you there, though a bit more expensive (but not always, as I have found out). The only other problem you could encounter is a pilot strike or some such thing. I missed one by a hair a couple of years ago going overseas. I was on one of the last flights - and hoping the strike would be over when I had to return 3 weeks later (it was). Another problem I ran into in Seattle last year, when Delta Air computers crashed. I could not get the boarding pass for the flight I was booked on, as did a long queue of other passengers - so I assume the plane left half empty while people were waiting in line to get boarding done manually.
In Seattle, there is a desk especially for Microsoft employees. I don't know what it was, but I asked a attendant there - they seemed like they had absolutely nothing to do, while the rest of the airport was a holy mess - but the nice lady there had pity on me and although I was not with Microsoft, she managed to re-book me onto British Airways - the great thing about this was that I arrived in Paris for my connection sooner than I would have with Delta!