Factual error: The train car in which Elle and the other passengers are held hostage is supposed to be an Amtrak type long distance railroad car traveling from El Paso to Dallas, yet on the inside of the car we can see a large poster showing the Washington, DC Metro system map.
Other mistake: When Morgan is showing the rest of the team the drivers license photos of the hostages on the train, every one of them is wearing the same shirt as they are on the train.
Character mistake: Close to the end of the episode, Dr. Reid says to the psychotic guy that was holding hostages, "M-theory cannot be proved." It should be "proven, " not "proved." Dr. Reid is supposed to be a genius, so he should be the last one to make such a mistake.
Chosen answer: Black SUVs are common police, military and dignitary vehicles around the world. It is not too much to assume they could be rented or owned by the police forces in the areas.
kristenlouise3
Other people have explained it but fore more information, federal cars would most likely be brought to the airport from the nearest agency, so they can drive out to their locations especially in rural situations.