Zaero is unofficial mission pack, developed by Team Evolve and published by Macmillan Software, which was released in 1998. Original web page is gone, but it was mirrored here:

I'm looking for their 44 meg demo (, since the link [fileplanet] is dead now. Ironically enough, full version floats on the net here and there, but I cannot find any more. Exact file size is 45156957 bytes.

Anyone got that and can upload it somewhere? Thanks!