I pack all my cards in a side pocket of my carry-on, "just in case." If I'm bumped to another airline or have a change in hotel or car reservations, I have the card handy to meximize the perks/benefits:
1. AAdvantage Platinum
2. UA Premier
3. HHonors Gold
4. Starwood Preferred Guest Gold
5. Thrifty BlueChip
6. National Emerald Club
7. Hertz #1 Club Gold