12 Squadron, based at RAF Coningsby, operates Typhoon fighter jets and is the UK’s first joint squadron since the Second World War.
The squadron had been scheduled to start flying training in March – however, that was delayed after the coronavirus outbreak.
Defence Secretary Ben Wallace said the formation of the squadron is “testament” to the UK’s “enduring friendship and commitment to Qatar”.
Dr Khalid bin Mohammad al Attiyah, Qatar’s Minister of State for Defence Affairs, said the first flight “marks an important milestone”.
A flag-raising ceremony at the base in Lincolnshire earlier this week marked the start of the flying training.
Qatari personnel are being training by RAF pilots and engineers ahead of the arrival of the aircraft from 2022.
Wing Commander Chris Wright, Officer Commanding 12 Squadron, told Forces News: “The joint squadron specifically will now grow its Qatari elements, to the point that we will train upwards of 16 pilots over the next few years ahead of the delivery of their own planes.
“So, 12 Squadron will continue to grow from where it is today, it will increase the complexity of the training that we do and will also involve some deployments out to the Middle East in support of their sovereign exercises.”
He also said the training is “truly is an exchange of ideas”.
“It would be naive of us at best to pretend that we don’t have anything to learn,” Wng Cmdr Wright added.
12 Squadron was stood up in July 2018 and will now prepare for exercises at the end of the year.