http://news.bbc.co.uk/1/hi/uk/7324964.stm
The expense of operations in Iraq and Afghanistan, combined with several major programmes for new equipment, have left the MoD with an estimated shortfall of at least £2bn over the next three years.
We're here to stay after 90 years, and we will be here for 90 years to come
But the crash of a Nimrod surveillance aircraft over Afghanistan in September 2006 - which was probably caused by a fuel leak and killed 14 people - has led to questions about whether the RAF is receiving enough cash to maintain the military requirements of the government.
"We never put the safety of one of our aircraft in jeopardy," says Sir Glenn.
"Older aeroplanes need more work to maintain the same standards we require - that's inevitable.
"We never undermine the safety of our aircraft. I'm not going to fly in an unsafe aeroplane and I'm not going to let my people do that either."
Air Chief Marshal Sir Glenn Torpy