From a summary of the issue I heard on LBC (UK radio station) a couple of days ago, this all stems from when the pilots agreed to a pay and pensions cut several years ago when BA was in financial trouble, and now that BA (and it's new parent company) is now back in profit, they want an inflation adjusted boost to put their pay and pensions back to where they should be.
Precisely this ... the problem in the UK media is this is being portrayed as "Evil high paid pilots holding the company hostage and ruining your holiday!".
Some other airlines did the same around 2009, but in a more pilot friendly way. For example at KLM the pilot's pay decrease to help the airline through the crisis was combined with a big increase in profit sharing bonus. At that time there was no profit to share, but now everyone is happy with the big bonuses.
BA was in financial trouble partly because their unionized staff are paid far too much. Putting their salary back "where they should be" (a novel concept) would just cause them to be unaffordable again. As will going on strike for 48 hours.
Basically BA is toast as an airline. They can't break their own union and are steadily being ground down by airlines with more flexible work forces.
