Yes, but you need to flip between compresses based on the map sets. It wasn't practical, manual if anything. The ISO method seems to work best, given todays drive speeds and capacities (can't wait for SSHDs to become cheap).
Concur! For many years I used Hatchet's Longbow Toolshop to swap in pre-decompressed maps and it worked very well. Caveat was, you had to know which map you were flying before starting the game or you could screw up your folder structure with an on the fly decompression.
In order to use some of Hatchet's experimental terrains (Kossovo, Bosnia) it was required to use this method as the terrains had to be combined with some of the pre-decompressed LB2 terrains to work and could NOT be directly used if decompressing terrains on the fly.
There was also a NOCD .exe which also required copying of the decompressed files to the HD where they would be decompressed as usual, but from the HD. THis worked and was fast
With mounted .iso files, the decompression is similarly incredibly fast, satisfies the CD check and I now prefer that method. The advantage over the NOCD method,other than not relying on a hacked .exe, is that you can locate the .iso files ANYWHERE (e.g. on an external or network drive) but I pretty much keep them on my main drive so there is no real disk space savings over the NOCD method.