The £5bn deal between Qatar and BAE Systems has officially become effective with the completion of the first payment to the manufacturer.
Qatar will acquire 24 Eurofighter Typhoon fighter jets and nine Hawk trainer aircraft instead of six from BAE.
The export deal also includes a support and training package for the aircraft, in addition to training and cooperation between the UK Royal Air Force (RAF) and the Qatari Emiri Air Force (QEAF).
Production of the training aircraft will be carried out at BAE Systems facilities in Warton and Brough in the UK.
The £5bn package of support for the deal, financing and insurance has been provided by UK Export Finance (UKEF).
The contract was signed between the two countries in December, and deliveries of the first Eurofighter Typhoon aircraft are expected to begin in 2022.
A new UK-based No 12 joint squadron for Eurofighter Typhoon has been established ahead of the scheduled delivery of the aircraft.
The squadron comprises military personnel from both the QEAF and the RAF, including pilots and ground crew members based at RAF Coningsby in Lincolnshire.
BAE Systems chief executive Charles Woodburn said: “This contract, effective today, represents a significant step in BAE Systems’ long-term relationship with the State of Qatar, as it becomes the ninth country to choose Typhoon.
“The proven combination of Typhoon and Hawk will provide the Qatari Armed Forces with the most advanced and flexible multi-role combat aircraft on the market today, along with best in class support and training.”
The 15.96m-long Eurofighter Typhoon is an advanced swing-role combat aircraft that has been designed with the capability to be simultaneously deployable for both air-to-air and air-to-surface operations.