Why do airlines encourage you to stay overnight on Saturday?

Dear Matt:

Why do airlines encourage, even require that no matter where you go, you stay overnight on Saturday? What do they care? It's almost like they don't want any planes in the air on Saturday. Why not?

-- Stewart Adellson, Chula Vista

They care because airlines historically have made a ton of money from business travelers -- the guy who finds out on Monday that he has to be in Syracuse for a meeting on Wednesday. They make their reservations on short notice, and in virtually every case the mug who's sent to Syracuse wants to get back home ASAP. Wednesday night. Thursday, latest. They pay top dollar for the ticket. So if you're a clever airline, you offer discounts only to people who make reservations two or three weeks in advance and who plan to stay at their destinations overnight on Saturday. For mom and dad and the kids going to Syracuse to spend a week with Gwamaw and Gwampaw, no problem. This is the kind of maneuver airlines are very good at. Actually getting you to Syracuse -- not so good.