The UK has sold 72 BAE Systems Harrier GR9 aircraft to the US Marine Corps for £115 million ($180 million) to use as a source of spare parts to support the USMC's fleet of Boeing AV-8B Harrier II aircraft, the Ministry of Defence said.
The MoD claimed that when added to the savings made from retiring the Harrier fleet from service, the sale contributes to an overall saving of £1 billion.
However, the UK had previously spent around £1 billion to upgrade the Harrier fleet in a project begun in 2005.
Peter Luff, minister for defence equipment, support and technology, said: "Harrier served this country with great distinction, but retiring it eight years earlier than planned was the right decision. Had we taken the decision in the Strategic Defence and Security Review to decommission Tornado instead we would not have been able to carry out the missions that were required simultaneously in Libya and Afghanistan. It was essential to retire older, less capable aircraft to allow us to invest in more modern, cutting-edge fast jets.
"As our operations over Libya proved, we have the capability to project decisive air power and can utilise our extensive basing and over-flight rights to great effect."
The sale of equipment to the US includes spares and associated support equipment.
Two aircraft will also be offered to museums to preserve the Royal Navy's military heritage.