JetBlue's $599 air pass is a deal if you live aboard planes

JetBlue's latest idea seems on first glance like it might have wings: An unlimited "All-You-Can-Jet" air pass, good from Sept. 8 to Oct. 8, that grants unlimited flying for $599.

The pass is pretty simple, as passes go. If there's an available seat, you can take it as long as you book by phone. Passes are on sale until Aug. 21, and if they're popular, they could sell out.

But considering how cheap seats already are at this time of year, you'd have to spend a huge amount of time in the air to make it pay off. You really would have to "jet-all-you-can" in order to make it work.

Essentially, you'd have to travel at least once a week for the month the pass is valid. And even then, you'd have to fly on some of the carrier's longer flights, and not its shorter ones, which are cheaper.

SmartMoney points out that to make the pass pay for itself, you'd have to fly round-trip from New York City to Boston, Chicago, and Denver -- all within a month. So the deal is much better for business travelers than for casual leisure travelers, and even then, only for business travelers who are always on the go.

Reaction from travel journalists has been tepid at best. USA Today reports one industry analyst as saying, it's just another way of having a sale without calling it one.

As further proof that sales are anemic in this late summer season, JetBlue is also trying to pump up late-summer sales by offering triple miles to its frequent flier members.

Although the idea of an air pass is an exciting one that makes for sexy headlines, in practice the prices have to be much lower for it to be a true steal.

Update: As fares begin to rise for the month that the path is valid, it's becoming increasingly possible to make a pass pay off. My advice is to price check the flights you'd want to take using it before you spring for it. It's now feasible to make your money back on two round-trip flights.