The impact of Russian sanctions is causing new problems for Boeing’s production of its 787 Dreamliner jet.

According to The Wall Street Journal, the manufacturer of a small but crucial component, RTX, struggles to keep up with demand. RTX had been making the temperature-regulating part in Russia but shifted production following Russia’s invasion of Ukraine. That worked when Boeing’s production was low, but now RTX’s new factory lines in the U.S. and U.K. aren’t making enough.

Boeing has warned that it won’t deliver as many Dreamliner jets as anticipated in 2024, and the slowdown will diminish the company’s already constrained cash flow, eventually having an impact on planes available to fly.

The WSJ says American Airlines blames Dreamliner delays for its decision to trim some long-haul routes.