1. Nobody cares how much your company flies. They care how much you spend. How much does your company spend per year on US & AA?
2. Most carriers -- all the legacies -- offer fully changeable fares. Change your reservations as much as you like and no fee. Anybody can book them. Just look on the website.
3. If you fly enough under #1, you can negotiate a discount with US-AA. But, that will all depend on how many millions your company spends.