I'd hazard a guess that in the U.S. minor or non-major modal tunes play a greater role in the dance scene than in the U.K., and more of a role than they used to. Certainly hornpipes (even when played as reels) are less in evidence here (in the U.S.) than they used to be, in contrast to the U.K. The growth in integrating southern old-time tunes into the dance repertoire means there are more modal tunes... I'm not at home where I could take a look at a modern book... The contrast between American contra dance style and English ceilidh style is not only in the dances, but the tunes, of course.

Here's a good page that compares the two sides of the pond, if you haven't already considered the topic: Bob Archer's "English / American dancing - a comparison".

~ Becky in Tucson