What happened

Last month, Boeing (NYSE:BA) terminated its deal to purchase most of Brazilian airplane maker Embraer (NYSE:ERJ) for $3.8 billion, sending Embraer stock into a tailspin. Only a few days later, however, news that Chinese airplane builder COMAC might want to step in and pick up the pieces sent Embraer stock flying again.

Today, the prospect of a bidding war is helping lift Embraer shares even higher -- up 13.1% as of 1:40 p.m. EDT.

Embraer E190 jet.

Image source: Embraer.

So what

As Reuters confirmed this morning, in addition to the COMAC interest previously reported, companies in both India and Russia are also evaluating "partnerships" with Embraer. According to Embraer itself, such partnerships would be "faster and more efficient" than selling the company's commercial airplanes division (which Boeing had wanted) outright. They would not be "of the size that the company had with Boeing," instead being more along the lines of cooperative agreements to build various aircraft -- with the partners providing the cash.

Now what

Good news for Embraer, you say? Investors seem to think so, and I'd love to be able to confirm that -- after all, I own shares of Embraer stock myself.

The truth of the matter, though, is that Embraer's vague description of the partnerships it is exploring, their characterization as being "still in an embryonic stage" -- and also Embraer's admission that it lacks cash to develop new airplanes on its own, has "reduced all investments," and doesn't even presently have a long-term plan for running the commercial airplanes business (that it thought was going to be sold) -- all suggest to me that this is an airship in search of a rudder.

If you were you, I wouldn't be buying Embraer stock -- and if I were me, I'd be seriously considering selling. (And I am).

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.