Boeing has agreed to pay Spirit AeroSystems up to $350 million in advance to keep producing products for it as the fuselage supplier works through a liquidity crunch. The jet maker said Tuesday that the advance payments are intended to help Spirit address high levels of inventory and lower operational cash flows.

Boeing Co. will advance Spirit Aerosystems Holdings Inc. as much as $350 million as the planemaker gives its most important supplier a financial lifeline ahead of the planned purchase of the company.