For 'Captain America' Johnston asked Simon to come up with vehicles that represented a '40s futurism'. That is, stuff with a look that would have been considered futuristic to people in the 1940s. Here's a look at Simon's design for Hydra's submarine:
A very sinister looking car.
I think Simon's designs pretty much fit the bill.
Here's a featurette on the light cycle:
Simon is doing designs for 'Oblivion' which is looking promising. Tom Cruise is set to star.
Here's Simon's Cosmic Motors website. The blog is a must for fans of sci-fi.
If you like his stuff he has a book, 'Cosmic Motors: Spaceships, Cars and Pilots of Another Galaxy'.