This is so cute, I can just imagine how much of an impact this interaction had on him. Of course he enjoyed the sirens and flashy lights, I'm middle age and even I would have enjoyed it so can see him being in his element.
It sounds like you have both had such a blast on your holiday together bonding. It's memories like that that will last forever with him and I totally get why you're the cool uncle 😁
We did a lot of things and I think he'll remember some, certainly in the short term; I even let him drive my cars, including the LandCruiser, whilst sitting on my lap. He told me he wants one now. I said I'll buy him one when he's bigger. I better start saving up.
What a freaking rad drive that must have been for him. I do the same with my niece sometimes and she giggles with glee so I get it. Not surprised that he wants one and I read it in your post about him asking for your truck. Maybe you should start a Hive account for him and then as he grows and it grows from curation, it can be the start of his LandCruiser savings account.