The aerospace company's shares declined more than the market today.Boeing (BA -5.49%) shares were down by more than 5% as of midday Friday. The move is impossible to look at in isolation, as the S&P 500 was down by 2% simultaneously. The reason for the latter is softer-than-expected jobs data that raised fears of a significant slowdown in the U.S. economy.A slowdown is bad news for the economy and the airlines that drive demand for Boeing's planes. Spending on consumer discretionary travel and corporate bus ...