Boeing is facing its worst crisis in years after two of its 737 Max planes have crashed in the last five months. As the plane remains grounded in most of the world, some airlines are beginning to rethink orders they have on the books. JPMorgan's top economist warned Friday that any slowdown in the planemaker's business could have repercussions for the entire US economy. The US' largest exporter is facing its most pressing crisis in decades, and now Wall Street is warning it could have an effect on the entire country's economy. As airlines begin to rethink their orders of Boeing's 737 Max plane, which is now grounded in most of the world after two deadly crashes, lost revenue for the company could draw down economists' measures of GDP growth - and even change how that economic growth is comprised - according to JPMorgan. The issues affecting Boeing's 737 MAX could begin impacting the economic data flow, Michael Feroli, the bank's chief US economist said in a note to clients Friday. For now, we believe it should have no short-run impact on GDP, as production of this airplane is continuing, but will affect the composition of GDP, implying more growth in inventories and less growth of business investment and gross exports. The 737 Max is likely to go down in history as one of the best selling planes of all time. But that same success could be a nightmare for Boeing if the crisis drones on much longer or gets any more severe. The nearly 400 planes already in service around the world have been grounded, and new purchases of Max jets make up 80% of Boeing's order book. If the issues are not resolved in a timely manner and production of the 737 MAX needs to be halted for a spell, JPMorgan said. It would take about 0.15% off the level of GDP, or about 0.6%-point off the quarterly annualized growth rate of GDP in the quarter in which production is stopped. For references, that's a bigger impact than January's government shutdown, the longest in history, had on the economy. That 35-day standoff subtracted about 0.4 percentage points from the first quarter's GDP reading. It could have an effect on multiple measures Total GDP output won't be the only thing affected by a slowdown in Boeing's orders. According to JPMorgan, it could affect the Census Bureau's factory goods report on aircraft shipments and orders as well as related inventories. The agency's monthly trade report also includes civilian aircraft exports Boeing's stock price, meanwhile, has fallen more than 13% since the Ethiopian Airlines crash in early March. Luckily, there is some good news. Any drawdowns from Boeing, should be made up in other areas. GDP should be largely unaffected for now, JPMorgan said. As weaker exports and business investment would be offset by more stock building. More on Boeing's 737 Max crisis: Boeing will start including a safety feature that customers previously had to pay for on all 737 Max aircraft Indonesia's flagship airline moves to cancel $5 billion order for 49 Boeing 737 Max 8 jets after deadly crashes DOJ has reportedly subpoenaed Boeing as part of a criminal investigation involving the 737 Max Europe and Canada are investigating the Boeing 737 Max themselves rather than trusting the US - another apparent snub of American regulators The crashed Lion Air 737 Max had the same malfunction the day before, but crew figured out how to stop it. The information never made it to the next flight Get the latest Boeing stock price here.