Installation: 

1: Install this mod: 
https://www.gta5-mods.com/vehicles/air-port-service-and-service-vehicles-template-pack 

2: Using OpenIV, add the "a_sign_1.png" texture provided to "C:\Program Files (x86)\Steam\steamapps\common\Grand Theft Auto V\x64e.rpf\levels\gta5\vehicles.rpf\maverick.ytd"