Hi, sorry for the late reply.
Thank you very much for your feedback on the plugin. I'm really glad to hear that you liked it.
I haven't used the Vehicle License plugin, but after reading the documentation, I understand that the player purchases a license to spawn a vehicle, which is valid indefinitely.
You can add the purchase of this license to the CraftingPanel as the command “vl.buy <vehicle type> <player name or id>” in the item settings line “Console commands executed after crafting (%steamid%, %username%, %amount%)”.
ItemRetriever retrieves items from: the player’s inventory, the player’s backpack (the one on their back), and the additional backpack (Backpacks plugin). It does not retrieve items from chests placed on the ground.