Well, that's what it's been called since 1962; what would you suggest?
Maybe they won't call it by name in the film because of that inherent dopiness. Come to think of it, I can't recall anyone referring aloud to "the Batmobile" in
Batman Begins.
There was actually a "Spidermobile" for a few issues back in the mid-seventies, but taht was pretty much a joke to begin with.
There was even a "Supermobile" that appeared off and on for quite some time. Corgi even made a die-cast miniature of it at one time.
And of course the Avengers have their Quinjet and the X-Men have their Blackbird. For some reason they weren't saddled with the requisite dopey names...
I'm betting they openly embrace that wonderful Lee/Kirby dopiness, and call the thing what it's always been:
The Fantasti-car.