I applied online. I interviewed at Southwest Airlines (Dallas, TX) in Aug 2016
Interview
They will call you and ask you some basic questions (ATA chapters) then if those answers are satisfactory will have an appointment for physical interview.The process will take in average around 90 days.
Interview questions [2]
Question 1
They will call you and ask about ATA chapters and their description (4 or 5 of them).
On physical interview, they will ask about Wiring diagrams of one random Aircraft systems usually the avionics part also flag notes, system elaboration