Here's something I wrote a while back, but I still consider it to be wholly valid:
"I want to draw your attention to the fact that even the FBI drew a parallel between the investigation of UFOs in the summer of 1947 and the Japanese Balloon wave of a few years earlier.
"The document quoted below shows that in the period of summer 1947 there was a 'mindset' that suggested disc sightings were not unlike the Japanese Fugo balloon sightings and investigations of a couple of years earlier.
"This demonstrates why - possibly - some people in the official world (even perhaps at the Roswell Army Air Field) made a psychological association between discs and balloons in the early period of summer 1947 and why they might have thought the 2 were connected (hence the Roswell Press Release). The following is extracted from a 1947 FBI document."
It is felt that the situation regarding these flying saucers and flying disks is very similar to the situation which was previously encountered by the Bureau during the past war in handling complaints arising out of the sightings of Japanese balloons. You will recall that at the inception of these complaints the Bureau conducted considerable investigation and located numerous balloons as a cooperative measure for the Army then informed that these were military weapons and that they would take over the handling of these completely. This they did and in an extremely short time issued a big press release as to the splendid work of the Army in locating these Japanese balloons. From the information available thus far it does not appear that these disks should be treated other than as a military weapon. Certainly the Bureau has no way to determine what experiments the Army and Navy are conducting and whether such might be arising out of experiments being conducted by them, nor do we have any way of determining how far the Russians have progressed in certain experiments and whether such might be the results of experiments by the Russian Army.
I continued thus: "So, the FBI drew a parallel between investigations into discs in 1947 with investigations into Japanese Fugo Balloons in 1944/45.
"And, based on their previous experience with the Japanese balloons, the FBI stated that:
'From the information available thus far it does not appear that these discs should be treated other than as a military weapon.'
"In other words, the FBI felt that disks were a military weapon and the line of thinking in official circles was that they should be treated - at an investigative level - in a similar way that the Japanese Fugo Balloons were investigated.
"That, in official quarters, people were seeing parallels between the Japanese Balloon saga of 1945 and the disc wave of only 2 years later, again reinforces why some people in the official world might have been inclined to think that disks were balloon- like and that balloon debris might be from a disc - because these parallels and ideas were already circulating.
"What we need to do is focus perhaps less on the reports, but on what was going through the minds of the official world when disc sightings began in the summer of '47. Were they perceiving these things as alien spaceships? For the most part: No. Were they drawing parallels between the Japanese balloon raids of 2 years previously? Yes. Official files - such as the FBI document above - reflect that attitude.
"As this FBI document shows, from the very beginning parallels were being drawn up in the official world between Japanese balloon based operations of 1944-5 with what was happening with disc reports in 1947.
"And if people in the official world were seeing/investigating unusual balloons from Japan in 1944/1945, then those same people might apply - as the FBI certainly did - the same line of thinking to what was being seen in 1947. Hence the circulating idea that perhaps discs were constructed upon balloon principles, or were at least inter-linked with all this somehow.
"That actually makes it much easier to understand why the people at Roswell - after finding a huge field of balloon debris - might have assumed there was a disc connection, (or far more importantly than a connection - a parallel) to balloon debris.
"That thought/connection/parallel was already floating around (particularly with the FBI, as we have seen)."