The Chief of the Air Staff predicted the Royal Air Force is likely to see "uncertain, complex and dynamic" challenges over the next 20 years.
Air Chief Marshal Sir Mike Wigston said the UK's incoming manned and unmanned aircraft capability, alongside advantages in space and cyber domains would all be vital.
But what do other experts think the RAF will look like in 2040?
Air Marshal (Retired) Greg Bagwell, president of the Air and Space Power Association, said the "big, exciting ideas" to look forward to include mixing autonomous systems with conventional manned technology.
A topic of much debate over the past decade, the level of autonomy granted to warfighting aircraft will dominate decision-making in the years to come, he said.
A commitment to developing artificial intelligence (AI) within the force has so far been capped at uncrewed, drone-style aircraft designed to fly alongside future manned systems such as the sixth-generation fighter, the Tempest.
The MOSQUITO and similar technologies may be armed with missiles but the UK still requires a human to have the final say on whether a trigger can be pulled.
Professor Peter Lee, an ethics expert at the University of Portsmouth, said controversy will surround "loyal wingman" aircraft actively engaging targets through AI processes, but the use of autonomous weapons against missiles heading for piloted jets would be largely accepted.
"How much of that automation is going to be allowed or be enabled to allow air power, if you like, to expand its horizon – I think that's probably the biggest area over the next 20 years," said Mr Bagwell.
WATCH: Air Chief Marshal Sir Mike Wigston gave a speech, including a segment where he spoke as if the year were 2040.
Greater AI capability could seem "extremely attractive" to those heading up air force spending, he added, with a potential for lower training and maintenance raising the question of RAF manpower - or jobs.
An "air force in-a-box" approach, running at lower operating cost and ready for use "in case of war", is trumped by the overall desire to multiply force for the same cost or less, Mr Bagwell explained.
John Sneller, head of aviation at the defence intelligence platform Janes, predicted a service strength of around 35,000 RAF personnel by 2040 - similar to today's head count.
However, he added that an expansive transport aircraft fleet (including C-130 Hercules, C-17s, A400Ms and Voyager aircraft) could be cut down.
Space has been the centre of much speculation in the forces world, with Boris Johnson visualising a joined-up approach for the military domains after pledging a £16.5bn defence boost in November 2020.
The prime minister mentioned how a soldier in hostile territory "will be alerted to a distant ambush by sensors or satellites or drones", while Prof Lee predicted a reconnaissance role for the RAF in space.
"Satellites at different orbits, with different capabilities, can help provide a three-dimensional picture of an operating space that the RAF will be deployed in, potentially," Prof Lee said.
As for the opposition, "highly-sophisticated threats" outside of Iran, Libya and Syria may push the UK towards "peer-on-peer" competition with advanced states over the coming decades, said Mr Bagwell.
Prof Lee said that smaller, non-state actors could pose different questions of unmanned aircraft to a "Tier One power", requiring the new technology to take on huge swarms of smaller drones instead of a single, more developed capability.