If the BA pilots go on strike, it will be pretty solid leading to large numbers of BA flights being canceled. The opportunity to rebook to other carriers or charter will be somewhat limited as the summer bookings are already very high. There is perhaps a chance of Bringing in Qatar again, but it would be of limited help. The bigger problem would be where to put all the grounded BA aircraft. There simply is not enough room at LHR. BA knows all this of course, and in the end I would be confident of a settlement being reached. The alternative is a disaster of epic proportions, which would cost far more than settling.