If you were to log in, you'd be able to get more information on your fellow community member.
Brad, Although jointly, senior pilots would benefit from the ability to trade airlines, a United senior pilot does not benefit from the ability of Delta pilots to join at a higher seniority level and vice versa. To negotiate these kind of reciprocal powers, they would need to form a cross-airline union, but that organization is much less effective at protecting the interests of its (senior) pilots for reasons explained above.