India’s cabinet on Monday approved a proposal to buy 10 C-17 military aircraft for more than $4 billion, a boost for Boeing’s manufacturing plant in Long Beach.

The deal is largest defense deal between the United States and India, according to wire service reports. The agreement to purchase the 10 heavy-lifting aircraft must be signed by both governments before the manufacturer begins to deliver the planes.

The C-17 is a large transport aircraft mostly used to airlift tanks, supplies and troops. It is built primarily in Long Beach.

“This is very good news for Long Beach,” Long Beach Mayor Bob Foster said to KNX radio’s Frank Mottek on Monday.

Foster said Boeing’s 4,000 employees in Long Beach and the more than 40 suppliers in the area depend on the C-17, but the cargo plane’s future is in doubt. The order from India, if approved, would keep the plant operating through 2013.”