mpclaw ~ You have to be careful with this strategy, because some (if not most) club memberships require you to have a ticket for that airline on that day to get in. They don't typically check for this, but they may be more likely to do so if there were major delays or such, exactly when an airline club membership is most valuable.

You may also want to look into the AMEX Platinum card, which gets you entrance into CO, NW, and TWA clubs (with a ticket on day of travel, but again, this probably is not usually checked).