> the amount anyone would actually pay is [...]

That's.... like a pretty shocking erasure of the idea of a demand curve given the forum here.

To be glib: no, that's not how it works. Increase the price and fewer people will fly, but the demand won't drop to zero. Decrease it and you make less money per ticket but the size of the market is bigger. At some point there is a local maximum, to which the market seeks.

But conditions change occasionally and the equivalent supply curve is moving rapidly because of the oil shock (i.e. it's more expensive to put planes in the air to service tickets you already sold). And things like the mess with Spirit are what happens when the market readjusts: the rest of the industry will (probably) backfill some of the lost capacity, but not all of it, and prices will (probably) rise a bit to a new equilibrium.