(Cheap~Delta) What is the cheapest day to book a flight on Delta Airlines?

(Cheap~Delta) What is the cheapest day to book a flight on Delta Airlines?   (Cheap~Delta) What is the cheapest day to book a flight on Delta Airlines? (Cheap~Delta) What is the cheapest day to book a flight on Delta Airlines? (Cheap~Delta) What is the cheapest day to book a flight on Delta Airlines? (Cheap~Delta) What is the cheapest day to book a flight on Delta…