If you visit the coordinates he gives in Google Earth (29.97213, -81.640047) you see the image just as he describes, so in that very limited sense, the image is verified. BUT:
1. On the lower left of the screen, is the date the image was taken. That is "Imagery Date: Jan 3, 2008". OVER TWO AND A HALF YEARS AGO. Pretty hard to miss!
2. There is no reason that I can see for assuming they are UN vehicles. Furthermore, there are no UN standard vehicles. The UN just uses whatever each host country has for them. There is no standard whatsoever. To identify an UN vehicle, if it's not blue or with big blue dots on the sides (which many don't) then you look for it's command markings, such as "KFOR" or what have you. Calling them "UN Trucks" without this positive ID is real sketchy.
3. When a US company exports thousands of trucks to another country or countries on a rush basis, might they not want to park them at an airstrip? Just a thought.

I have seen this before the photo used in this is about 4 years old. Google maps does not do real time. We really have no idea why these vehicles were staged there.