Last week, Delta (NYSE: DAL) announced its intention to order as many as 400 new narrow-body jetliners. If you're a Boeing (NYSE: BA) shareholder, the math here is really simple: 400 of the planemaker's 737-800 jets, times an average list price of just more than $80 million apiece, equals $32 billion in potential revenue up for grabs.

Alas, there's no guarantee Boeing will be doing the grabbing.

Crisis, opportunity, you know the drill
If Delta's invitation creates a $32 billion opportunity for Boeing, it also poses a risk. The announcement coyly explains that Delta has invited "several" airplane builders to bid for its business -- suggesting a wider field than just the usual suspects, Boeing and Airbus. It almost certainly implies that Delta is considering Embraer's (NYSE: ERJ) larger regional jet offerings for potential purchase. The CSeries jet now available from Canada's Bombardier may also be in the running.

Who knows? Delta might even accept bids from Russia's Superjet or China's C919. That said, even if they're outfitted with parts from reputable, established manufacturers such as General Electric (NYSE: GE) and Eaton (NYSE: ETN), I imagine that Delta views such latter bids more as stalking horses than dark horses.

Cynics will argue that as a heavy user of Boeing and Airbus planes, Delta will stick with the tried and true, rather than opt for anything shiny and new. But even in that case, the fear of having to beat phantom competition might spur Boeing to offer Delta its planes at too low a price, slashing profit margins and hoping to "make it up on volume."

Foolish takeaway
For the record, I consider that as the biggest risk, too. Nonetheless, remember that when Airbus won its ballyhooed $5.1 billion order from Virgin America yesterday, Virgin observed that if it hadn't given the contract to Airbus, its second choice would have been Bombardier and its CSeries jet -- not Boeing.

While some Fools pooh-pooh the risk of Bombardier stealing share from Boeing, make no mistake: The threat from Canada is real, and it's growing.

Embraer is a Motley Fool Stock Advisor recommendation, but Fool contributor Rich Smith does not own shares of, nor is he short, any company named above. Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.