The rhetoric coming from Cruz and Walsh in the last few years have been along similar lines - and why not; it is their prerogative to maximise income for their business and its shareholders.
They are anti R3 at LHR because it would jeopardise their position as the top dog in London, not for its environmental arguments.
A third rwy doesn't seriously threaten BA's position as top dog at LHR as (1) the new slots will be distributed amongst many carriers, and (2) BA will be entitled to a proportion of the new slots.
Does the value of BA's LHR slot portfolio count as an asset on the balance sheet? If so, it would be a better reason to oppose a third rwy, as the secondary slot market ends once the third rwy is operational, consequently the slot portfolio becomes worthless in cash terms.
Just asking the question.