In the case of ALPA, you have national resource supporting local MECs. It's the local MEC (ie. pilots at YOUR airline) that negotiate with the help of labor lawyers, contract administrators, R&I experts, etc...

A single company union cannot afford the resources that a national union brings to the table, especially at a regional airline. Think of it as a Costco membership in that the national union brings leverage in the "purchasing" power to all members that a single group couldn't afford. So, number 1 would be available resources to members.

Next, and crucial to our profession is patterned bargaining. Non-union airlines have managements that are successful at brining/keeping wages and benefits artificially low (it's their job!). Membership in a nation union allows/produces a higher chance of success in pattern bargaining. Think of it as a tug-of-war, union airlines are trying to drag regional pay up, and non-union managers are trying to drag it (keep it) down.

Finally, remember that contracts go well beyond pay. Having vast union resources in economic analysis will allow a pilot group to cost a contract to make sure that a company can afford it (hint they will ALWAYS cry poor) and that pilots don't leave money on the table. In addition to pay, a pilot group should be able to improve work rules, QWL, benefits, etc.

In short, participation in a national membership will require as much or more participation by line pilots and you'll pay about 1.95% of W2. Pilots at YOUR airline will have to do the committee work day in day out. Your MEC will have to debate the resolutions and make the decision. National does NOT show up and do all this for you (locally). But, when it's time to draw on resources available to the union a national union does have much greater resources than an in-house union ever could - and that is the benefit.

The national union in question is not perfect, but I'd pick it over an in-house any day.