Both Arrow and The Flash have long teased the existence of Green Lantern within their shared universe via the occasional Ferris Air reference. Ferris Air is of course the airline that Carol Ferris owns and operates, and is the employer of none other than Green Lantern Hal Jordan. While the occasional throwaway Ferris Air Easter egg has been nothing more than a fun bit of fan service over the last few years, The Flash kicked things up a notch this week and threw the rumor mill into high gear when it delivered the biggest Hal Jordan clue yet.