Iz,
You say "...if my company had bought a A330.." Herein lies the problem I think. The ex-Swissair guys refuse to accept that Crossair have taken them over because Crossair did not pay a brass bean for the Swissair equipment. It was given to them. They look upon the whole SWISS exercise as a merging of Swissair and Crossair and hence their contention that seniority should be based on entry date into either Crossair or Swissair. Nothing like a merger/takeover or whatever to muddy the seniority issue as I am sure we have all seen in the past elsewhere. Regarding the disparity in salaries - I have no idea. Perhaps a moderate contributor like Rob. V. can answer that one. Both unions are fighting hard for their members - some might say TOO hard. It is a great pity the 2 sides cannot come together, but reading the comments posted here that would be wishful thinking.