[cybrjoe]

Don't all airlines already sell standby tickets? I'm guessing the demand on the average flight isn't enough to cover the chance someone won't show.

[mseebach]

I've never seen standby tickets on sale in a first order way. Usually, it's when you're on a rebooked or connecting flight, they'll offer you standby on a better (but sold out) option.

[vannevar]

If demand were too low for standby tickets, the flight wouldn't be in danger of overbooking in the first place.