DC-9-15 Expansion for McDonnell Douglas

This add-on features the McDonnell Douglas DC-9-15, created by @bushiido444. It includes a single "Aero California" livery and does not support multiple liveries simultaneously.

Credit for the livery goes to @bushiido444. Installation instructions are provided in the Read Me file.

Changelog:

V1.1: Modified the vehicle sound for accuracy.

I am open to requests for vehicle add-ons. Specifically, I can create add-on versions of modded vehicles that currently exist as replace vehicles. Please note that I lack the knowledge to convert models myself.

@SkylineGTRFreak maintains a website listing his upcoming model conversions.