The VTOL...
...appears on the following maps:
- Airport
- Brooklyn Bridge
- Central Cavern (sometimes)
- East River
- Hydro Dam
- Skyline
It is controlled by AI and follows a preset path. Get to a high point along the path and jump in the loading bay. There you can mount one of the two MGs with

and start spewing fire. 10 kills with this and you can add another Trophy to your list.