Boeing Co. is heading closer toward finalizing a deal with China to sell as many as 500 aircraft, according to people familiar with the matter, a transaction that would end a sales drought that stretches back to US President Donald Trump’s last visit in 2017.

China will need an estimated 8,800-plus planes over the next 20 years to meet rising demand for air travel, according to Boeing’s commercial- market outlook. About 60% of that demand would come from airlines expanding their fleets, while airlines replacing older jets with more fuel-efficient models would account for the rest.