Wirelessly posted (BlackBerry: BlackBerry8530/5.0.0.601 Profile/MIDP-2.1 Configuration/CLDC-1.1 VendorID/417)

On a nonstop flight from anywhere in California to anywhere in Hawaii, BA charges 12,500 Avios one way in Coach. If you have to fly from SMF to LAX on AA to connect there, BA would charge 17,000 miles. These rates apply year-round, but you can only redeem for the lowest-tier award seats on AA or AS.

By contrast, AA charges 17,500 miles (off-peak season) or 22,500 miles (peak season) for a one-way, low-tier redemption on AA, AS, and/or HA. Connecting flights, if needed, are included at no extra charge when redeeming AA miles.

Both AA and UA miles expire 18 months after last activity (earning or redeeming). There are lots of options for earning or redeeming miles in both programs: just check each airline's web page to see how to earn or redeem miles.