Joint Combat Aircraft The Joint Combat Aircraft ( JCA ) is the official designation of the United Kingdom Ministry of Defence used for the F - 35 Lightning II , formerly the Joint Strike Fighter , and the result of the Joint Strike Fighter Program . Programme history . The JCA programme began in 1996 as the Future Carrier Borne Aircraft ( FCBA ) , a replacement for the Royal Navy ' s Sea Harrier intended for operation from the RN ' s CVFs . The requirement for the FCBA was set out in Staff Target 6464 which specified a carrier - borne aircraft capable of air defence of naval and ground forces and self - escorting ground attack . As the Royal Navy version of the JCA ( and potentially Royal Air Force versions ) would operate from the two newly ordered Queen Elizabeth Class aircraft carriers , the selection of the aircraft was closely linked to the design of the carrier . Candidates for the JCA were thus listed by carrier type : Following the 1998 Strategic Defence Review the Navy ' s Harrier FA . 2 s and RAF Harrier GR . 7 s were merged to form Joint Force 2000 ( later Joint Force Harrier . As such the requirement was revised to include the replacement of the RAF Harrier force ; this led to the renaming of the project as the Future Joint Combat Aircraft ( FJCA ) in 2001 . Later , in the third and final name change of the project , the word " future " was removed . Aircraft selection . On 17 January 2001 the UK signed a Memorandum of Understanding ( MoU ) with the U . S . Department of Defense for full participation in the Joint Strike Fighter project , confirming the JSF as the JCA . This gave the UK significant input into aircraft design and the choice between the Lockheed X - 35 and Boeing X - 32 . On 26 October 2001 the DoD announced that Lockheed Martin had won the JSF contract . On 30 September 2002 the MoD announced that the Royal Navy and RAF will operate the STOVL F - 35B variant . At the same time it was announced that the carriers would take the form of large , conventional carriers , which will be adapted for STOVL operations . The carriers , expected to remain in service for 50 years , will be convertible to CATOBAR operations for the generation of aircraft after the F - 35 JCA . In 2007 , the Ministry of Defence confirmed its order for two Queen Elizabeth class aircraft carrier s , to enter Royal Navy service in 2015 - 2018 . Technology transfer . The UK has invested US $ 2 billion ( GBP £1 . 08 billion ) in development funding for the JSF . Britain has also worked for five years for an ITAR waiver to allow greater technology transfer associated with the project . The effort , backed by the Bush administration , has been repeatedly blocked by U . S . Congressman Henry Hyde because of his concern about potential technology transfer to third countries . On Friday 27 May 2006 President Bush and Prime Minister Tony Blair issued a joint statement which announced : The CEO of BAE Systems Mike Turner , the British contractor on the plane , had complained that the U . S . has not given the UK ( and his company ) access to the crucial source code of the plane ' s software , thus making it impossible for the UK to maintain and modify the JSF independently . On 21 December 2005 an article was published in the " The Herald " saying that MPs viewed as " unacceptable " the U . S . refusal to grant access to the source code . The article quoted the chairman of the Commons Defence Select Committee as saying that unless the UK receives assurances of access to the software information , " the UK might have to consider whether to continue in the programme " . Following on from this Lord Drayson , Minister for Defence Procurement , while on a government visit to Washington to speak to members of Congress , took a firmer stance . He was quoted as saying , < nowiki > " We do expect [ the software ] technology transfer to take place . But if it does not take place we will not be able to purchase these aircraft " < / nowiki > , and has mentioned that there is a ' plan B ' if the deal falls through . A suggested likely option was the development of a navalised Typhoon . Mike Turner has said it was not what he recommend , but : A navalised Typhoon may have required the RN ' s Queen Elizabeth class aircraft carriers to be built with catapult s , adding to their cost and capability . Basing . In November 2005 it was announced that the F - 35 main base will be RAF Lossiemouth , Scotland . Seven other sites were considered ; RAF Marham , RAF St . Mawgan , RAF Cottesmore , RAF Wittering , RNAS Yeovilton , RAF Leeming and RAF Kinloss . Lossiemouth was selected due its existing facilities and access to training areas .