You know, I've been thinking about that "grills over the intakes thing," and I think I've figured out why there aren't--correct me if I'm wrong, those who actually know what they're talking about. In any case, at 400 MPH, I'm thinking that the grills would do no good--they'd get smashed straight into the engine, and might in fact do even more damage. Right?

I am the Doctor, and THIS... is my SPOON!