Drawings of planes and technical details about wartime aircraft were found scribbled on walls at the Belle Vue Royal Hotel in Aberystwyth.
The RAF said pilots trained in Aberystwyth during the war and were probably billeted at the hotel.
It has sent details of the find to its air historical branch in London.
The RAF's spokesman in Wales, Squadron Leader Peter Sinclair, described the drawings as an "incredible piece" of wartime history.
Pictures of wartime fighter aircraft and bombers, one complete with a pilot smoking a pipe, were discovered when the hotel stripped the walls of the room to decorate.
Technical data about the wingspan of British and German planes and dates from 1943 and 1944 were also uncovered.
"We know that during the war years, Aberystwyth was the home of No.6 Initial Training Wing (ITW)," said Sqn Ldr Sinclair, who has visited the room.
"My research leads me to believe that the hotel was used as billeting for the students of the training wing and may even have been used as a classroom or some other type of learning centre.
"Certainly this would explain why they took great trouble to record aircraft data on the walls of the bedroom - they would retire to rooms to do homework and revision and the data they needed to absorb was recorded on the walls."
Phrases, such as Bing for king and Joe can't sing, were also discovered daubed on the walls.
These may have been used as a training aid to remind pilots about a certain procedure, added Sqn Ldr Sinclair.
The hotel's owners now plan to re-decorate the room.
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