Even the best run pension schemes are finding it hard to accomodate everyone in the present economic environment and very few companies now offer a final salary scheme to new employees.
The BAA's owners and it's Pension Trustees know only too well that there are, with due respect to all the employees within the company, very few jobs within BAA which are so specialised that they can't offer training to new employees.
Consequently they can fill most vacancies by offering a competetive salary and don't need to offer a final salary scheme to new staff.
I can't see what strike action over this particular issue will achieve, other than inconveniencing the customers.