I guess I found the answer to part of my question. According to a new posting on the TWA website:

EARN 15,000 AVIATOR MILES ON TRANS WORLD ONE FLIGHTS THROUGH SEPTEMBER 15

When you purchase a full CTWONE fare* and fly round trip between the U.S. and Europe, you'll receive a bonus of 15,000 Aviator miles.

15,000 Aviator miles are enough for a free domestic round trip ticket in markets less than 750 miles each way.

The Trans World OneŽ service bonus offer, effective June 15 through September 15, 1999, will be credited to your Aviators portfolio after you complete your eligible international roundtrip. And there's no limit to the number of Trans World One bonuses you can earn during the three-month promotion period.

Prior to actual travel, you must register for the Trans World One bonus offer by calling 800-325-4815 and entering code 89663.

* Includes corporate rates, excludes other discounts.

(End of quote) I guess this means the answer is, "No, you can't get 15,000 bonus Aviators miles from a short hop domestic TWA flight in business class." I wish MSN were more thorough on these things.