Well this makes things really interesting:
"As part of the agreement, America West and TWA will accept bookings beginning in first quarter 2001 on more than 500 flights operated by both airlines."

Is this the end of the CO+HP relationship?
I think not, HP provides CO too much access to the west coast. But, TW is another carrier that will provide access to east coast cities. This may be an early knell for the HP/CO relationship.

HP ticket on TW metal = OP miles?
I bet this is handled like the NW/KL issue.
Ticket on HP= OP miles.

If your primary program is OP I suggest the following:

HP tkt= OP credit
TW tkt= FF credit (redeem on CO,NW,HP,TW)


BSL