Pilots striking will not be supported by the UK travelling public, and that is a lot of public in FlyBe terms - "Pickets In Porsches" will be headlines - regardless of what you earn at FlyBe, your earning potential is far greater than the average UK worker...
Public support is irrelevant in terms of industrial relations. It shouldn't even be a factor when it is time to decide to walk out or not. Of course it would be unpopular, how could it be otherwise?