Southwest Airlines is the most famous carrier in the United States for its "2 Bags Fly Free" policy, allowing every passenger to check two pieces of luggage (up to 50 lbs each) at no extra cost, regardless of the fare class. Internationally, many full-service flagship carriers still offer a two-bag allowance for transoceanic flights. For example, Japan Airlines (JAL) and ANA (All Nippon Airways) famously allow two checked bags (up to 23kg/50lbs each) in Economy Class on international routes. Other airlines like Air India, Emirates, and Qatar Airways often provide a two-bag allowance for specific international destinations or higher economy fare tiers. Domestically in the US, most other airlines (Delta, United, American) charge for even the first bag unless you have elite status or a co-branded credit card. Always verify the specific "piece concept" on your ticket, as baggage policies can vary significantly based on the specific route and booking class.