If you have enough money to fly on a private jet, it’s no sweat to pay a $2,500 annual membership fee for a smartphone app. Right? This was the theory behind Blackjet, an app that set out to help wealthy citizens of the world book seats on private jets.

Among the early adopters of Blackjet were such FPs as Jay Z, Will Smith and Ashton Kutcher. According to Valleywag, though, Blackjet is running out of cash, and out of time, as complaints about the functionality of the app have grown over the past few months and rumors about its certain doom are beginning to swirl.

One recent tweet by Juniper Networks (News - Alert) executive David Koretz spelled out the disappointment:

The only App Store review of BlackJet is by user LoOods [sic], who gives the product “one star,” calling it “horrible” and asking the company to “send me back my money.”

While two poor online reviews does not a failing company make, it’s hardly a good sign that BlackJet’s chairman jumped ship (or plane, as it were) a few months ago.  The Blackjet executive whose catching the most flack for the company’s downward spiral is former chairman Shervin Pishevar, an investor in Blackjet, as well. Pishever had allegedly promised to raise $15 to $20 million, money that has yet to come through.

Blackjet’s folly is a good lesson the need that a great idea (or at least a great idea for rich people) doesn’t always translate to a successful app launch. Who knows if another private jet reservation app will be able to take off, but here’s hoping that it one does, it’s also able to stick the landing.