I'll have to research, but I don't think AS has protection against 76 seats. DAL/UAL have been around for 80 plus years. JetBlue has been around for less then 15 years. Their time will come. As their costs continue to rise, management will look to outsource. Since the pilots have no union, they won't be able to stop it. VA pays Regional wages, and also has no union. Spirit doesn't really have a route structure conducive to RJs. No hub and spoke makes it tough to support RJs. SWA scope has never been challenged. It's pretty easy to hold the line when no one attempts to move it.

United pilots will likely fail in holding on to less then 50/70 seats. There is simply zero leverage to do so. The best they can hope for is to limit airframes to 76 seats and a MGTOW of 86,000 lbs, then limit those airframes based on mainline flying. If mainline shrinks, so do the RJs.