As mentioned earlier, the airlines just love punishing consumers with the highest fares and surcharges they can find for flying on high-volume days. Just avoiding those days will knock $10 to $20 off the peak surcharge each way, but it'll also help drop the airfare overall. "Airfare is the least flexible of travel costs, meaning there's often not a lot of wiggle room," Travelocity's Brown says. "That said, flying on Tuesdays, Wednesdays and Saturdays tends to be cheaper." They don't mean just a few dollars cheaper, but $60 to $80 cheaper each way judging by FareCompare's analysis of fares from Dallas-Fort Worth to Miami. It only gets worse as the summer progresses. A one-way flight leaving Sunday, June 27, costs nearly $90 more than the same flight leaving Tuesday, June 29. Considering that flying on Sunday, Monday, Friday and even the occasional Thursday can put that much of a premium on a flight, it may be worth it to book a Wednesday-to-Tuesday trip the next time out. "Those are not coincidentally the slowest days for air travel," FareCompare's Seaney says."That's why you see most airline summer sales restricted to those days." The absolute cheapest flights require some physical as well as logistical sacrifice. Travelers just have to ask themselves if the best fare is worth losing sleep or missing a meal. "If you're going to depart within a day and you're looking for a cheaper flight, the rule of thumb is to fly hungry," Seaney says. "The cheapest flight of the day is the first flight out where you have to get up at 4:30 a.m. and miss breakfast;' the next cheapest is around lunch; and the next cheapest is around dinner."