I have police , fire engines and ambulance on my sims... go to Planet Earth 28 or The Spoiled Diva Freebie store.... I am listed here

Wayda's shop in Lani mall in osgrid has a collection of airport emergency vehicles

I have a couple of mesh ones at OpenBox on FurValleys Plaza. Their unscripted so if you're looking for something that moves and interact with should look elsewhere.

I think i saw some at Wrights Plaza on Osgrid, sorry i cant remember the store name, also i think Hawks Shack Shops at Great Canadian Grid have some as well.