The RAF needs "more investment" if it is to continue running the range of operations ministers demand, the head of the force said.
Air Chief Marshal Sir Stephen Dalton, who is overseeing a huge overhaul in the service, said he was trying protect the core of the RAF amid a period of spending cuts and redundancies.
Sir Stephen told the Guardian: "The key factor is that if we are to meet the requirements laid upon us, there is no question that more investment will be needed to achieve that.
"What I am seeking to do is maintain core competencies and bricks on which we can then build the future."
Without "genuine increases", the RAF would find it "very difficult to maintain levels of capability," he said.
Last autumn, the Government signalled its intention to shed 17,000 posts, some through "natural wastage", from the armed forces in a bid to save nearly £5 billion over four years.
The RAF last month spelled out its plans for 2,700 lay-offs following last year's strategic defence and security review.
Sir Stephen's comments come as the Army and Navy prepare today to unveil the process under which they will make 5,000 and 3,300 redundancies respectively.
He said the RAF could continue its work in Afghanistan, the Falklands and Libya "on current planning", but added: "That does bring you nearer the point that you have just about exhausted the bag.
"It's a heck of a lot to be doing at one time."
The immediate priority was British efforts in Libya, he said, where planning was "on the basis of at least six months".
The Government has set a target of 2020 for revamping the Uk's defence strategy.
Sir Stephen said extra cash was needed from the next comprehensive spending review in 2014-15, but claimed Prime Minister David Cameron had acknowledged this requirement, the newspaper said.
The RAF chief accepted the need for reform, but added: "What we are seeking to do is make sure that the adjustments are recoverable (and do) the least long-term damage."
Sir Stephen said air power was "essential" for nearly all types of operations and warfare, and dismissed suggestions the service was too expensive.
He also stressed there was "no question" the country needed an independent RAF.Reuse content