Here's an animated Learjet . There are 2 models - animated with undercarriage, and static low poly with no undercarriage. They both have 2 LOD stages. The script basically just poses the animated model in the correct position (landing gear lowered etc). The engines turn, the landing gear can be raised and lowered, and the wheels turn. The animation frames for these animations can be found in the FPE file.
https://www.dropbox.com/s/1dbbe7qh4t5xdaa/Learjet.zip?dl=0
