I attended the show on Friday and Saturday this year. On Friday, I was looking for items to add to my railroad topical collection. Since trains on stamps is one of the most popular topics and has a very large number of issues, finding new material for that topic was pretty easy. But that's a story for another site.
When I mentioned my collecting interest of March 4 to the dealers at the show, most of them pointed to the large boxes of covers for me to dig through. A couple of them recognized that March 4 used to be the date of the U.S. presidential inauguration, but my budget for the show wouldn't accommodate $50 per cover. So it was off to the lower cost bins for me. It took a while to look through all the dealer stocks that I examined. While most of the time there weren't any obvious connections, I did find eight covers that had a March 4 cancellation on them.
The most recent was this cover commemorating the 5-year anniversary of the Einstein stamp issue from the U.S.
The next cover, in descending order of postmark date, was a much more ordinary cover.
One year further back and I have a show cover from 1977.
The remaining covers that I found for March 4 were much more like what I was hoping to find. Especially, the rest of the covers were postmarked outside the U.S. The first of these, from 1975, was a first day cover from Israel.
Moving back in postmark dates again, the next cover I found was another first day of issue, this time from Niger in 1967.
The next cover I acquired from the show moves us back three decades to 1937.
The last two covers that I found at the show go together. Again, the markings on the front of the cover are a day off, but both show appropriate back stamps. The first cover commemorates the first airmail flight from Winnipeg, Manitoba, to North Battleford, Saskatchewan,... front...
So those were the covers that I got from NTSS this year to add to my March 4 collection. As I build an album to hold and display these items, I'll be doing a little more research into each of the covers. I'd like to learn more about the stamps that were used and the cancellations that each cover obtained in its travels. When I have more information, I'll post it, but if you, dear reader, have more information on any of these covers, please let me know in the comments.