Interesting thread. As a boy in the 1960s I used to tramp around the airline offices in London, of which there were many. There were a few that told me to get lost but most were very accommodating. A couple let me loose in their stock room and I'd leave with all sorts of goodies, like posters, labels and stuff.
When I "grew up" and started getting interested in cars, girls, music etc, I decided, in a moment of madness that I have regretted ever since, that I didn't need them anymore and threw them all out.
About thirty-odd years later I was working in a Middle East country where life is pretty quiet and I occupied my down time on eBay. I remembered the airline timetables I'd disposed of and sought to make amends. Now I have an impressive and varied collection (I'm impressed anyway) of over 2000 timetables from all over the world. I prefer older timetables with the 'columnar' format rather than the more recent, and actually more convenient, 'quick reference' format. The columnar format is good for the multi-stop flights that were prevalent back in the day as it showed the route and stops made for each trip. I have examples from the 1930s right through to the early 2000s though the columnar format had pretty much disappeared by the 1990s.
I have catalogued them on Excel spreadsheets, N.America, which includes the Bahamas, and the Rest of the World, sub-divided into Continents. Some continents are harder to find than others, Africa for example. I haven't bought any recently though I do still occasionally look.
My most recent items are:
Jun1 1950 KLM with age related label - March 2024
Sep28 1958 Transocean Airlines (TALOA) - May 2021
Jul1 1969 BOAC - Sep 2023 (A holy grail for me - This was when I made my 1st trip to the USA)
A 1976 VARIG in a seat-back flightpack - Jan 2024
I've tried to attach copies of the spreadsheets to this post - but it's not a format that is allowed.