September 3, 2008 By Justin McHenry

Southwest Airlines announced yesterday that, beginning September 9, the airline would only except credit cards and debit cards for on-board purchases — no cash allowed. Southwest is not the first but is the largest airline to go cashless on board.

Alaska Airlines recently announced its “cashless cabin” and some smaller airlines have gone that route as well. US Airways has tentative plans to go cashless next year.

Flight attendants on Southwest flights will have hand-held card readers in order to take payment for alcoholic drink and Monster energy drink orders; other drinks and snacks remain free.

Holders of the Southwest Airlines Rapid Rewards credit card may welcome the news, as they receive double miles for Southwest purchases, now including their on-board purchases.