Some same day turns available, without even a red eye. Example:

US Airways New York (LGA) to Washington (DCA) - Mon, Nov 5
US Airways 2163 Dep: 7:00AM Arr: 8:09AM 1h 9m Airbus A319 Economy (E)

US Airways Washington (DCA) to San Diego (SAN) - Mon, Nov 5
US Airways 65 Dep: 8:50AM Arr: 11:36AM 5h 46m Airbus A320 Economy (E)

US Airways San Diego (SAN) to Washington (DCA) - Mon, Nov 5
US Airways 66 Dep: 12:30PM Arr: 8:06PM 4h 36m Airbus A320 Economy (E)

US Airways Washington (DCA) to New York (LGA) - Mon, Nov 5
US Airways 2188 Dep: 9:00PM Arr: 10:10PM 1h 10m Airbus A319 Economy (E)

Cost per passenger (including taxes & fees) $241.20

Surely the experts will be able to find more convoluted routes that will improve the ROI.