Joel Rose

That's driven up the price of jet fuel worldwide, even in the US, which is a net exporter of jet fuel.

The price has nearly doubled in the past two months.

That is putting pressure on all airlines, really.

But in the case of Spirit, problems really ran much deeper than that.

How so?

Well, the airline has been in trouble for years.

It was a pioneer of the ultra low cost business model where airlines keep their fares way down by stripping away the amenities that travelers had previously taken for granted and then charging extra for them.

That's not a model for everybody, but it did make flying accessible for a lot of people who otherwise could not afford it.

And for a while, Spirit made money, but then the big legacy carriers created their own versions of

they called basic economy fairs.

And Spirit had hit hard times.

It tried to merge with a bigger airline, JetBlue, but the Justice Department sued to block the merger.

Since then, Spirit has filed for bankruptcy twice.

In recent weeks, the airline sought a $500 million federal bailout from the Trump administration, but those talks failed to yield a deal.

And finally, Spirit

ran out of money.

The airline announced early this morning that it has ceased operations after more than 30 years.

Spirit says anyone who booked flights directly with the airline will automatically get a refund, though if you booked with a voucher or a credit, it is not clear yet if you're going to get compensation for that.

And some other airlines have agreed to cap their fares for travelers who were holding tickets with Spirit.

Well, airline CEOs have been asked a version of that question a lot on earnings calls over the last few weeks.