From FlyerGuide Wiki

Note: Elite-level members are automatically upgraded based on availability.

Silver: For members who fly 25,000 miles or 30 segments during a calendar year on qualifying America West Airlines, America West Express, Big Sky Airlines, British Airways, Hawaiian Airlines or Northwest flights. Benefits include:

• 25% mileage bonus on paid flights.
• Unlimited first class upgrades on Y and H fares confirmable two calendar days prior to departure.
• Unlimited first class upgrades on all paid fares confirmable one day prior to departure.
• First class check-in at airport where available.
• Private toll-free number for reservations and information.
• Priority standby status on all flights.
• Early boarding.
• Preferred seating.
• Check-cashing privileges at any America West ticketing location.
• 50% discount at package service center.
• Car rental and hotel discounts.

Gold: For members who fly 50,000 miles or 60 segments during a calendar year on qualifying America West Airlines, America West Express, Big Sky Airlines, British Airways, Hawaiian Airlines or Northwest flights. Benefits include the above listed, plus:

• 50% mileage bonus on paid flights.
• Unlimited first class upgrades on Y and H fares confirmable anytime after ticketing.
• Unlimited first class upgrades on all paid fares confirmable three days prior to departure.
• Unlimited standby upgrades two hours prior to departure on all paid fares.
• Unlimited companion upgrades confirmable two hours prior to departure (based on availability).
• Guaranteed confirmed reservations on America West operated flights when purchasing a full Y fare coach ticket at least two days prior to departure.
• Travel profile.

Platinum: For members who fly 75,000 miles or 90 segments during a calendar year on qualifying America West Airlines, America West Express, Big Sky Airlines, British Airways, Hawaiian Airlines or Northwest flights. Benefits include the above listed, plus:

• 100% mileage bonus on paid flights.
• Platinum Top Value Awards allow members to redeem awards free of capacity controls and at reduced mileage rates.
• Unlimited first class upgrades on all paid fares confirmable three days prior to departure.