Southwest Airlines may be the victim of a chilling act of vandalism, after messages that appeared to be scrawled in Arabic writing were found on the underbellies of several jets.
The graffiti, which began appearing in February on 737-model planes, has been found more often in recent weeks, according to Los Angeles radio station KNX-1070.
The writing appears to have been etched using a chemical process and is visible only after an auxiliary power unit is turned on.
Southwest Airlines spokeswoman Brandy King said the company is “conducting an internal investigation.”