The UK government will buy nine new marine patrol planes from Boeing in a decade-long deal worth £3bn.
The Ministry of Defence's deal for the submarine-hunting P-8A Poseidon aircraft also covers training, maintenance and support.
Boeing will build a new £100m facility for the planes at RAF Lossiemouth in Moray.
The US company will also deliver 50 Apache AH-64E attack helicopters to the British Army.
Boeing expects to create about 2,000 new UK jobs in the coming years by expanding its maintenance and support operations for both military and commercial customers in Europe.
Prime Minister David Cameron announced the P-8A deal at the Farnborough Airshow.
He said it showed that the UK was open for business despite the referendum vote to leave the EU.
"Whatever uncertainties our country faces, I want the message to go out loud and clear: the UK will continue to lead the world in both civil and defence aerospace," Mr Cameron said.
The P-8A planes will fill a gap in the UK's defence capabilities that has existed since 2010 when the Nimrod was retired.
Boeing has doubled its UK workforce and more than doubled its annual spending with the UK supply chain over the last five years to more than 2,000 people and £1.8bn respectively in 2015.
Source: BBC News