Bill Lyon’s Challenger II can be downloaded for free from AVSIM.com (cc11qc2f.zip) This awesome package include a full selection of variants and was originally payware. You’ll probably find other ultralight/microlights on AVSIM and the other freeware file libraries.

Also Lago do an Ultralights package, an upgraded FS2002 package which in my opinion is showing it’s age now. It can be purchased from Simmarket here I believe you may also find other ultralight paywarre models on simmarket although I can’t comment on the quality as I don’t own any of them.

Hope This Helps !

Bruce