You might do better to get a credit card branded to the airline you are traveling on. Even better might be something like Amex Preferred Rewards gold, which gives 3X on airfare and the points can be transferred to a variety of airlines.

There is no way you can get the miles for the people who are actually flying, only for the spending associated with the tickets.

You could also consider signing up for cards with large bonuses where you might normally have trouble meeting the spend requirement. For example, I don't know what the current offer is, but the Amex Biz Gold gives 3X on airfare, and there have been bonuses of 50K (rarely 75K) points for signing up and spending $10K in 5 months. Similar situation for Chase Ink biz card.