Try popping an email to this site

http://www.popularflying.com/

looks like they have a good collection and might be able to help. Some interesting cover art online there!

It looks as if this will be a useful and interesting website in due course but, for the present, the contents of only one of the featured issues of ‘Popular Flying’ has been put onto the site – and, regretably, that’s not one of the 1937 issues!