The nine US carriers we read every time you search.

Delta usually wins the New York ↔ West Coast and Atlanta ↔ anywhere matrix in our results. Their basic-economy fare hides a checked-bag fee that we surface before you click through.

Strong on Chicago, Denver, Houston, Newark and the West Coast Pacific. United’s premium-economy fares often beat Delta and American on the SFO transcon market.

American owns Dallas/Fort Worth, Charlotte, Miami and Philadelphia in our results. They run very tight basic-economy rules — no overhead bin on most routes — which we flag in the result card.

Two free checked bags and no change fee on standard fares. Southwest is the regular winner on Texas, Florida and Las Vegas short-hops in our search panel. Note: Southwest does not appear inside Kayak; we link to southwest.com directly.

Best legroom in basic economy on US carriers, plus free Wi-Fi on every aircraft. JetBlue is the regular winner on the Northeast ↔ Florida market and Boston transcon in our results.

Pacific Northwest specialist. Alaska usually owns Seattle ↔ California and Anchorage market in our search. Saver fare gets a small overhead bin, unlike basic economy on the Big Three.

Ultra-low-cost. Lowest sticker price out of Denver and Orlando in most weeks. Carry-on, seat selection, and printed boarding pass each cost extra — we add an estimate of the realistic fare next to the headline price.

Ultra-low-cost out of Fort Lauderdale, Las Vegas, Detroit, Chicago. Cheapest published one-way fare on most short Florida and Caribbean trips. We surface the bag and seat add-ons before you click.

Minneapolis-based hybrid carrier. Strong leisure routes to Mexico, Florida, the Caribbean and West Coast. Sometimes wins MSP ↔ Las Vegas / Cancun pairs by a wide margin.