Alaska Airlines is the best overall domestic airline, according to a survey from WalletHub, the personal finance website, that measured carriers across 15 metrics. They ranged from cancellation and delay rates to baggage mishaps and inflight comfort. They also considered costs in relation to inflight amenities “for the sake of fairness.” Other findings:  cheapest carrier was Frontier Airlines; most reliable was Delta Air Lines (lowest rate of cancellations, delays, mishandled luggage and denied boardings); most comfortable was JetBlue Airways (inflight experience with free amenities, extra legroom and free snacks and beverages); least complained about were Southwest Airlines and ExpressJet Airlines; and safest was Alaska Airlines (incidents and accidents). WalletHub compared the nine largest US airlines, plus three regional carriers.