Spirit's 7.57% off sale mocks American Airlines' loose seat problems

Spirit Airlines has made a mark with bold advertising for its fare sales. Some of its fare-sale promotions have pushed the bounds of good taste, but today the self-described "ultra-low-cost carrier" appears to be taking direct aim at one of its major competitors: American Airlines.

Spirit's latest promotion -- a sale for 7.57% off base fares – seems clearly directed at rival American's recent in-flight problems with seats coming loose from the floors of two its Boeing 757 jets.

In its promo, Spirit runs an image with this message in call caps: "WE LET FARES LOOSE, NOT SEATS! 7.57% OFF."

An animated image showing loose screws plays as the ad appears on Spirit's website.

Spirit's promos have long pushed the edge of good taste, including one from last year that poked fun at former California Gov. Arnold Schwarzenegger's affair that helped seal his divorce from Maria Shriver. Another previous Spirit fare promo played off the fictional Hispanic Supreme Court character "Ochita Suprema," an effort that drew ire from some as being insensitive.

Other apparent targets of Spirit ads in recent years: Tiger Woods following his sex scandal and one-time 2012 Republican Presidential candidate Herman Cain.

Spirit's latest ad, however, is somewhat unusual in an industry where carriers rarely throw rivals under the bus in such an public way.