I love Grant and Frank's in-joke.
The crook who's driving the car is the Toad (newbie).
But he seems obviously based on the old arch enemy of Courageous Cat and Minute Mouse, the Frog, right douwn to the Derby hat!
Courageous Cat and Minute Mouse were also invented by Batman (co-?)creator Bob Kane.
And they had a flying car, too.
Nice touch, mates!
Best,
Ed