the rules in sabre say (as of today):

172N . 6. WITHIN THE US/CANADA - 1 NONSTOP OR
173N . SINGLE PLANE TRANSCONTINENTAL FLIGHT
174N . PERMITTED. TRANSCONTINENTAL FLIGHT IS
175N . DEFINED AS TRAVEL BETWEEN THE
176N . FOLLOWING CITIES:
177N . BWI/BOS/FLL/BDL/ LAS/LAX/OAK/
178N . MIA/EWR/NYC/ORL/ - AND - PDX/SAN/SEA/
179N . PHL/SJU/YYZ/DCA SFO/SJC/YVR