Still a favored perk of executives, the corporate jet has quickly become a symbol of excess. Yet as troubled corporations try to unload their fleets to stem the public relations headaches, the wreckage may lead to the discovery of still another crash: the manufacturers of business jets themselves.

Crash landing
Amid strikes at manufacturing giants like Boeing (NYSE:BA) and order delays, there is a growing realization that plane inventories are growing and that a weak aftermarket can't support higher pricing. Both Boeing and jetliner rival Airbus are suffering from fewer plane orders. Through the beginning of February, Boeing had a net decline of 13 planes after it reported 31 cancellations, while Airbus had 12 cancellations for a net decline of eight planes. But it isn’t just the big commercial manufacturers that are suffering. Plane makers of all sizes are cutting back production and planning layoffs.

Bombardier's LearJet and Challenger programs are facing job cuts totaling more than 1,300 employees as demand falls, while Cessna Aircraft parent Textron (NYSE:TXT) is laying off 30% of the subsidiary's workforce. The Gulfstream Aerospace division of General Dynamics (NYSE:GD) also plans to cut mid-size aircraft production in half this year.

An idea takes wing
As the inventory of late-model used planes climbs and utilization rates show marked reductions, manufacturers and parts makers are feeling the decompression occurring in the industry. Cabin interior manufacturer BE Aerospace (NASDAQ:BEAV) recently noted that not only did business jet activity decline 20% in the fourth quarter, but the price for used aircraft declined by 25% as well. Rockwell Collins (NYSE:COL), a manufacturer of cockpit electronics, cut 2009 guidance from that given just this past November because of the deterioration of the business jet market. It plans to cut 600 jobs and freeze executive salaries.

This might lead investors to think that those who arrange for jet-sharing among executives could see business soar. That would be companies such as Berkshire Hathaway's (NYSE:BRK-A) NetJets, Bombardier's FlexJets, or Flight Options, a former subsidiary of Raytheon (NYSE:RTN). Yet they risk incurring extra costs if they run afoul of availability guarantees or have to charter outside aircraft. Since their utilization is higher, they put more miles on their craft, reducing their planes' residual values and further pressuring the aftermarket.

Off the tarmac
Warren Buffett once disparaged the notion of investing in airlines, saying he'd need to enroll in a 12-step program if he ever caught the bug again. Investors might want to apply that thinking to the plane manufacturers, too. While depressed valuations make it seem like their shares could take flight, industry trends suggest the plane makers may instead encounter turbulence. Investors deciding to wing it anyway better hope their companies have a pilot like Chesley Sullenberger in the cockpit in the event they have to ditch into the Hudson.

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Fool contributor Rich Duprey does not have a financial position in any of the stocks mentioned in this article. You can see his holdings here. The Motley Fool has a disclosure policy.