You don't have to be an attorney to understand the last two words in your post.

It's Delta's property. If you want to distribute flyers or hang posters for Pilots For Kids, you have to get Delta's permission. It's their property. You are an employee, and have to abide by their rules. Those rules are in the FOM, and in the case of pilot organizing, in the PWA.

If you own property, you can prevent the Westboro Baptist Church from planting yard signs on your lawn.

Your property...your rules.

See? I just saved you from having to pay more to AMFA's lawyers to explain that.

You're welcome, brother!