Sun Airways is a Colonial transport system operational at the time of the Fall of the Twelve Colonies.
Giana O'Neill had been under their employ on Caprica as an aeronautical engineer who performed safety inspections of their craft. After becoming a deckhand aboard Galactica, O'Neill comments to Galen Tyrol that she would ground craft for potential failures like those she saw on Raptor 702.
After witnessing the awkward conversation between Tyrol and Sharon "Boomer" Valerii, O'Neill pointedly asks Tyrol how long he's been seeing Valerii, noting that "her old job" had been replete with "office romances" (TRS: "The Plan").