I had thought that a Stropp had been a razor sharpening belt,(or behind tanning tool

)Hence the term 'stropping a razor'
or also the Australian interpretation 'If-you-##%&**!-kids-dont-shut-up-im-going-to-give-you-the-stropp'(now thats poetry!)
or 'dont get stroppy with me young man ,(insert above )'
If the inference is taken to be sharpening a very fine blade the word becomes quite a logo for a fighterplane.
Just a thought....