Absolutely NOT in favor of a national seniority list. I'm a member of an independent union. My company is financially sound. My company would be a purchaser of other companies and then they would take selected assets and selected key employees only. My company is in no danger of ever being bought out by another and therefore, I have no worry of having to start over at the bottom of someone else's seniority list.
It seems that the only people in favor of a national seniority list are those working at financially struggling airlines and those that are in danger of being bought out.