The planemakers are keeping quiet about exactly how many layoffs there will be. Sources, however, say the number could reach 3,000 between Cessna and Hawker Beechcraft.

Six months ago, Wichita planemakers were having to figure out how to fit new plane orders into their already full production schedules. Now, they are trying to figure out how to adjust to customers who can no longer take delivery or are trying to defer their deliveries months and years out.

"The business aviation industry today has decreased faster than any other time in its history, as far as sales activity," said Brian Foley, aviation analyst.

The biggest buyers for corporate jets over the past decade have been fractional ownership companies. The largest of those companies is NetJets, which is owned by Berkshire Hathaway, the Warren Buffet Company.

Sources say only a few months ago, NetJets was ready to receive more than 40 Citation jets this year. With the market collapse, they have put the brakes on deliveries and might only take 10 or fewer Citations.

Foley says he wouldn't be surprised if some planemakers shut down for periods of time this year. No one has said that would happen, but it's happened as recently as 2003 when Cessna shut down production for several weeks during the downturn.