archive.aero is a free viewer for historical FAA sectional charts. Drag the timeline to see the charts in effect on that date. It's about 7,600 chart sheets stitched into one mosaic per edition. The scans come from the National Archives, the FAA, and charts contributed by the public. It's built on GDAL and PMTiles, so there is no tile server or backend. The browser reads tiles straight from Cloudflare R2 with range requests.

I'm a student pilot in North Texas and I always wanted a "ForeFlight time machine" to see what changed between editions. The gaps are at https://archive.aero/contribute (mostly 1970 to 2005) if you have old charts and would like to send them to be scanned.