达美和西北将对国际航线第二件托运行李收费50美元 Delta and NWA will charge 2nd bag for $50 international flight

更新：只对美国至欧洲航线适用。中美航线仍旧免费两件行李。

Delta reference:

Checked Baggage—International

Currently when traveling to or from cities outside the United States you can
check two bags, per passenger at no extra charge. For tickets purchased on
or after April 21, 2009 for travel beginning July 1, 2009, customers in
economy class will be charged $50 US (or the local equivalent currency) for
the second checked bag. Exceptions to the second checked bag fee include:

* First and Business Class passengers
* SkyMiles and WorldPerks Elite members (Executive/Platinum/Gold,
including Flying Colonels)
* Active duty military members traveling on orders
* Passengers who purchased tickets prior to April 21, 2009
* Passengers who are confirmed on a Full Y class Economy ticket.

http://www.delta.com/traveling_checkin/baggage/baggage_allowance/index.jsp#bagfee

NWA reference:

Checked Baggage Allowance:
For tickets purchased on or after April 22, 2009 for travel on or after July
1, 2009

http://www.nwa.com/travel/luggage/checked.html#domestic