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In terms of passenger traffic in and out of Seattle-Tacoma International Airport, Northwest Airlines ranks sixth among the top 12 airlines serving the airport. Delta ranks seventh. Here's how a possible merger between the two could affect customers:

Frequent-flier program. Whose would prevail? Northwest's WorldPerks program has a good reputation for availability of award travel and for automatic upgrades of elite members compared with Delta's SkyMiles program. Unlike WorldPerks miles, SkyMiles expire after two years if you don't use them.

Airline Web site. Northwest's clean, fast site, www.nwa.com, is consistently ranked among the two best airline Web sites. Delta's site, www.delta.com, was in the cellar of an August 2007 ranking by industry analyst Forrester Research.

Business customers. Whose elite status program would be retained? Northwest's Elite program and Delta's Medallion program are similar but not exactly the same. For instance, Northwest fliers can achieve elite status by miles or by flying 30 so-called segments (flights) in a year, while Delta uses only mile totals to grant elite status. Platinum Elite members on Northwest get 125 percent bonus mileage when they fly while Delta's Platinum Medallion members get 100 percent.

Security

New rules for carrying lithium batteries

To help reduce the risk of fires, air travelers are no longer able to pack loose lithium batteries in checked luggage.

Passengers can still check baggage with lithium batteries if they are installed in electronic devices, such as cameras, cellphones and laptops. If packed in plastic bags, batteries may be in carry-on baggage. The limit is two batteries per passenger, and affects shipments of non-rechargeable lithium batteries. For more information, see www.tsa.gov.

New York

Now's the time to find bargains in the Big Apple

Forget the dog days of August.

Now is New York City's slow period, when hotel rates are as low as they're going to get. And tourism officials have launched a campaign to entice visitors.

At www.nycvisit.com, click on "NYC Open: Book 2008" and find more than 250 offers, such as discounts of up to 20 percent off the lowest rate published by certain hotels, or two-for-one admissions to museums or reduced-price theater tickets.

Passport changes

Government prepares for new passport cards

No final word yet on when U.S. citizens will need a passport or an as-yet-to-be-created alternative for land and sea border crossings involving Canada, Mexico, Bermuda, the Bahamas and the Caribbean. But the State Department is preparing now.

Officials will begin accepting applications for a "passport card" Feb. 1. The card will be cheaper and smaller than a passport and good only in the circumstances noted above. The card, which lasts 10 years for adults and five for children, will cost $45 for adults and $35 for children under 16.

The most controversial aspect of the passport card: It will contain a "vicinity read" radio frequency identification chip that can be read from a greater distance than the chips being put in passports.

Compiled by Seattle Times staff and news services.