If you can drive a car, then with sufficient training, you can do it

John O'Hara Flying instructor

Learning basic flying skills in a light aircraft is something many people pick up very quickly, he says.

"What you need is someone that is sensible, alert, has good eye-hand co-ordination and motivation."

"If you can drive a car, then with sufficient training, you can do it," he told BBC News Online.

Training programme

But obviously there are differences between the kind of flying done in a small plane in good visibility and the kind needed to move a modern airliner around the sky safely.

Cockpits across Boeing's range of airliners are similar

Potential commercial pilots training in the UK take two years to qualify.

"You could go to the Oxford Air Training School at Kidlington, put down your �40,000, and they'd take you through the private pilot's licence, into the commercial stage and qualification," said Mr O'Hara. But much of that training is of an academic nature.

"The mechanical skills don't tend to cause people problems. It's the academic bit that takes time."

Commercial pilot training would typically involve learning to fly a small, twin-engined plane, then a conversion course for a specific airliner.

Taking off and landing is the tricky bit

John O'Hara Flying instructor

"You do what is called multi-crew conversion. You really do need more than one person on the flight deck of an airliner," he said.

Companies like Boeing and Airbus Industrie try to keep the controls of their aircraft similar or identical across their range, to minimise the amount of familiarisation needed.

Computer simulation

Someone who could fly a relatively small airliner like the Boeing 737 would find the controls of a bigger one like a 757, 767 or 777 familiar.

Commercial pilot training

Two year course Private Pilot Licence Commerical training on light twin-engine craft Multi-crew conversion on simulator

A conversion course needed to teach a newly qualified commercial pilot how to fly a large plane like a Boeing 767 can be carried out using a commercial flight simulator.

There is no need to have actually flown the real airliner to gain the qualification. The skills needed to aim an airliner at a building would, of course, be far more basic.

"You haven't got to take it off. You haven't got to land it," Mr O'Hara explained. "It's a one-way trip. You don't need to be a skilled pilot: I could teach you in half an hour the skills needed to aim at that tower."

Simulation games

There has been speculation that flight simulation software on home computers could have been useful to those who destroyed the World Trade Center.

" I suspect that that wouldn't be sufficient," said Mr O'Hara. "I've got one on my laptop and, do you know, I find them pretty difficult to fly."

He said that someone who had learnt to fly a very simple type of aircraft and then sat in a commercial cockpit simulator would have been able to aim the airliners used in the US attacks.

"Quite honestly, you could just get a big scale photo of the cockpit and look at where everything is," he said.

Landing the 'tricky bit'

"The things that are difficult to teach in flying are judgement, timing and control. People make huge progress in early exercises, but taking off and landing is the tricky bit," he added.

Finding the World Trade Center towers should not have been too difficult for the hijackers.

"Navigation is fairly simple. It's far easier in the air than on the ground and if you're not too dim it's not a problem."

The hijackers may well have had knowledge of how to use radio navigation beacons to work out their position and find New York, Mr O'Hara said.