When members of the Royal Flying Corps were spotted high in the trees of Reading, it must have raised questions about how exactly the recruits, sitting in fuselages wedged between the branches, were helping the war effort.
But the cadets were actually being taught important flying skills.
More than 30,000 of them passed through the town during the course of World War One, including soldiers from as far afield as Russia, America and Australia.
At the start of the war, the University of Reading had offered up its buildings for military use, and before long they were being used by the corps for its "No 1 School of Military Aeronautics".
The tree exercises were just one of a number of unusual techniques used to prepare recruits for the battlefield.
Aviation historian Andrew Bird explained: "It was to give the officers a scale of height, with reference to things on the ground.
"They climbed up the ladder, got in, and an instructor used to shout instructions to them and they had to look left or right and tell them what they could see. It was very rudimentary.
"It must have been really strange for the local population walking along the road to see young men sitting in fuselages doing simulations of a bomb run or observation with instructions being shouted at them."
Another training exercise involved soldiers sitting in a Maurice Farman fuselage which was attached to rails at the university's Wantage Hall tower.
A pilot sat in the rear of the plane, with an observer in the front. They were then launched along the rails, which crossed the quadrant over a map on the ground containing small scale models - to make them feel as though they were flying at 2,000ft.
The map was also rigged up to pyrotechnics which would go off to represent bomb blasts.
Mr Bird said: "They were launched from the tower and the observer had to makes notes on a knee pad.
"It was very much like a 'death slide'. They heaved the front of the fuselage off the edge and as it came down the observer had to plot where the pyrotechnic 'bomb' bursts were coming from.
"The courses went on until 8pm so they could get an idea of flying in the dark.
"It must have been quite exhilarating I think, but also quite frightening to be launched off the Wantage Hall tower and then fly across the quadrant to the other side.
"You think of all of the health and safety rules today, but people were learning new skills and they really had to make it up as they went along as nothing had been done like this before.
"This was the first mechanised war. So officers brought up with cavalry charges had to get used to modern technology. This was obviously done off the cuff as they had to think about how to do new things."
The pioneering four-week course trained pilots, observers and equipment officers.
The majority of the men came from the army. Instructors came to teach for between three and six months and it was offered as a rest from the Western Front.
Mr Bird said: "The course... covered everything from bombs and instruments, rigging, technical storage, motor transport engines and quartermaster stores.
"In 1916 about 10,000 officers came through Reading because it was estimated that with losses on the Western Front and other campaigns they would probably need about 15,000 men to cover the list of casualties.
"So it was a continuous stream of men arriving and leaving Wantage Hall."
After their initial training many of the pilots would go on to have three or four hours of flying lessons in Coley Park or Brooklands in Surrey.
Among those who received their flying certificate at Coley Park was William Earl Johns, who wrote the Biggles books.
A small number of women were also trained as riggers and fitters, learning how to maintain the wires and canvas on the aeroplanes.
Julia Cox, whose grandmother was a rigger in the Royal Flying Corps, said: "We knew that she had done something because we have got a propeller blade at home, so we thought there was some connection there.
"How she got the propeller blade, I have no idea. I'm very proud of my grandma, that she managed to do this job and achieve it in such a new area of technology, which flying was. Also she was a female and she just got on with it and got stuck in."
Mr Bird said as the war continued women were called on to do more and more jobs.
He said: "In the beginning men did the work. But when they realised that men up to the age of 51 had to go to the frontline, some of the jobs were taken over by women."
The first training manuals for the air industry were also produced in Reading, with 300 women employed to illustrate them.
The training school ran for three years and its end came almost as quickly as it began.
"It was there one minute and gone the next. Alfred Palmer turned down the offer from the RAF to buy the whole of Reading University in November 1918," Mr Bird said.
"Had he not turned down that offer Reading would have gone on to be the equivalent of RAF Holton. But everybody just upped sticks and left."
- How the University of Reading played host to the Royal Flying Corps and how the war was fought in the skies over Britain.
- How did WW1's battle in the skies change warfare?