Wall Street analysts have a long list of economic bellwethers. But lately, rather than looking at steel production, prognosticators are looking to another indicator: private jet use. This week Merrill Lynch announced that they will be cutting down on business jet usage, as the investment firm looks to cut back on costs, news which garnered an article in The Financial Times.

Meanwhile, tech blogs, like Silicon Alley Insider, are once again buzzing with rumors as Apple’s latest SEC filings show that CEO Steve Jobs was flying the corporate jet four times as much in the June quarter as he did during first three months of the year. The speculation is that Jobs is flying the G-V on trips to Asia to shore up suppliers, or perhaps to ink deals with telecommunications companies to bring the iPhone to India and Russia. Jobs, who has the use of the G-V built into his contract, could, of course, have been using the jet for some vacation time with his family—but that probably wouldn’t make for much in the way of good Apple speculation. At any rate, the $102,000 worth of flight time that Jobs billed Apple for this last quarter pales in comparison to the $550,000 he billed them for in the last quarter of 2007. When those reports first became public, a Morgan Stanley analyst recommended buying Apple stock.

In a globalized world, private jets have become an integral business tool. With supply chains that stretch thousands of miles, and multiple markets in regions around the world, the business jet isn’t just a convenience for executives, but a necessity. Our advice to anyone looking to plot the course of the economy? Look to the skies.