In the current US aviation market of 2026, Southwest Airlines remains the only major carrier that offers two free checked bags to every passenger as a standard policy, regardless of the fare class purchased. This "Bags Fly Free" initiative has become the hallmark of their brand. Beyond Southwest, other airlines generally charge for bags unless you meet specific criteria. For example, Alaska Airlines, Delta, United, and American Airlines will typically offer two free checked bags only to passengers flying in First or Business Class, or to high-tier elite members of their frequent flyer programs. Additionally, many co-branded airline credit cards provide the first bag for free, but rarely the second. Military personnel on active duty or traveling on orders also frequently receive a generous allowance of three to five free bags on most US carriers. If you are flying on "Ultra-Low-Cost Carriers" like Spirit, Frontier, or Allegiant, you will not receive any free bags, and in many cases, even a carry-on bag requires a significant fee, making Southwest the undisputed leader for travelers with heavy luggage.