[Hallicrafters] "Airplane" Noise on Short Waves

[Freeberg, Scott (STP)]

I remember hearing airplane noise as well as a kid with my shortwave.  I wonder if it was RTTY broadcast.  When I was a radioman in the Navy during Viet Nam, I used copy RTTY fleet broadcast.  I sounded like an airplane I guess.  It consisted of a many individual RTTY channels with super narrow shifts, transmitting in that bandwidth.  With a really good receiver you could slowly tune up the frequency and pick out the individual mark/spaces for each RTTY channel within in 3 Khz or whatever bandwidth.  Do you think thats what the airplane noise is?
73, Scott WA9WFA