The new Chief of the Air Staff says the Royal Air Force's purpose is "more important than it's been for many years".
In his welcome video message, Air Chief Marshal Sir Richard Knighton addressed those serving in the RAF and told them the service needs to "be ready to fly and fight".
"That is fundamentally why we exist," he said. "What we do is vital for the country, for our families and for those who we fight alongside in the other services."
The new chief said: "All of us have a part to play, whether regular, reserve, civil servant or contractor."
He added that success within the service depends on "having the people and the infrastructure we need to get the most out of it".
Sir Richard listed his top three priorities as "operational focus and mindset, our people and our infrastructure".
"The world we live in is more volatile and contested than at any time in recent history," he said, adding: "It's clear to me that the operational challenges are greater than we've faced for decades."
"For more than 100 years, the Royal Air Force has had a noble and vital purpose; protecting our country, our interests, and our people from the air.
"This is more important than it has been for many years."
ACM Sir Richard takes on the role of service chief as results from the UK Regular Armed Forces Continuous Attitude Survey 2023 have shown that overall service life satisfaction among RAF personnel has dropped to the lowest level since 2007.
The results also showed that attitudes towards financial-related aspects of service life have continued to decline.
The new Chief of the Air Staff added: "We need to make sure we recruit, train and, most importantly, retain the people we need.
"And we must continue to invest more to improve where we live and work."
ACM Knighton thanked his predecessor in the role, Air Chief Marshal Sir Mike Wigston, telling current personnel: "I'm very much looking forward to working with you, supporting you and listening to your ideas over the next few years."