How so? They can't put tariffs on foreign planes purchased by foreign airlines, and most of the airlines in the world are not American.
"The World Trade Organization said on Thursday the United States had ignored its request to halt a subsidized tax break for Boeing Co in its main plane-making state of Washington as a 15-year-old transatlantic trade row edges towards tit-for-tat sanctions."
https://www.reuters.com/article/us-eu-usa-aircraft-wto/wto-s...
At least in China, the government is the one that has the final say on everything, and the state-owned corporations have to do what the government wants. Here, the corporations get to do what they want, but they still get subsidies from the government but without being required to operate in the interests of the government or the nation at large.
According to their most recent 10-K, the Defense, Space, and Security business unit represents about 23% of Boeing's revenue and 13% of their profit. Some portion of the Global Services revenue comes from government contracts as well, though, so the true contribution is higher.
https://www.sec.gov/cgi-bin/viewer?action=view&cik=12927&acc...