Airmail covers from the treasure hunt

I'm hoping you all recall my little treasure hunt thread.  I have a banker's box of stamps and "stuff" that a friend gave me that belonged to his mother.  I'm down to the bottom and these are the latest things I've come across:  some airmails from various countries...some on full covers, and some clipped close and still attached to what's left of the cover.  I'm hoping to get some feedback on these.  See anything interesting?  All of these were sent to the Willys-Overland factory here in Toledo...you know, where they built Jeeps.  But these were before the Jeeps and pre-WWII.  They are all from the late 1920's to the early 1930's, if my initial research is correct.