The airline will now tighten the rules on access to its SkyClubs. If you travel a lot, one of the least aggravating ways to spend time in an airport is in an airline club or lounge. If you need a quiet place to get a little work done, have some coffee or a light meal, or just want to avoid the mass of travelers, a lounge isn't a bad place to wait for a flight. Some of them are even pretty nice. For example, Delta has recently made a big deal of the investment it is making in its lounges,...