The Chief of the Air Staff says the RAF must be "prepared for an era of confrontation".
Air Chief Marshal Mike Wigston told Forces News that these are "uncertain times", adding that he is focused on making the RAF future-ready.
"There's no question we live in uncertain times and we have to be prepared for an era of confrontation, increasingly competitive...and countries and states not playing by the rules," he said.
"This is something that we've seen from Russia, from Iran. These are things that we need to prepare for.
"Getting the Royal Air Force ready for that challenge of the next generation, building the next-generation air force is a key part of my programme for this year and going into next."
Looking back on 2019, Air Chief Marshal Wigston said there were a series of milestones that made the year successful.
"We took delivery of our first Poseidon maritime patrol aircraft, returning to that really important airpower role protecting our oceans," he said.
"We've seen our first operational deployment of Lightning, which was a great success...it's been a great year for operations."
2019 also saw the end of the Tornado after 40 years of service in the RAF.
The jet was the backbone of the RAF but Air Chief Marshal Wigston said he was looking to the future with the Typhoon and F-35B providing a "world-class combat airforce".
Asked if he had a message for RAF personnel this Christmas, the Chief of the Air Staff said he wished personnel a "happy, healthy and prosperous new year."
"If you are away from your family and loved ones, I look forward to you getting back together as soon as you can," he said.
"Wherever you are, thank you very much for your service."