A colleague asked me whether concentrating all of her flying on a single airline would get her free upgrades to first class. Without going into the particulars of just how much flying (25,000 miles in a year? 50,000 miles? 75,000? 100,000?), here was my oversimplified answer —

Different airlines have different upgrade policies.

With American you can either use miles OR upgrade certificates that you earn by flying (you basically earn 25% of your flying in first class free). United, Delta, and USAIrways have similar policies.

With Continental, Northwest, and America West you get all of your domestic upgrades for free. They process them based on your status and give the seat to you if it’s available. No additional cost.

Alaska Airlines is my favorite program of all — elites who fly 35,000 miles or more with the airline in a year get to confirm first class seats when they book their tickets, regardless of fare. Fly 15,000 miles and get first class seats for free if they’re available 48 hours before the flight.

With elite status, you have to fly each year to maintain it — with two exceptions

• If you reach 1 million miles in American’s program, you get lifetime Gold. (2 million miles = lifetime platinum.) This is total miles earned in the frequent flyer program (flown miles, credit card miles, etc etc). This is not 1 million mile balance — you can SPEND your miles and still earn this. United and Delta have similar programs, but they require FLYING the million miles.
• Some airlines only downgrade you one status level per year even if you fail to fly enough to earn that status level. Delta and USAirways usually do it this way. So, if you fly 50,000 miles with Delta this year and no miles next year, you’d still be at the elite level that corresponds to 25,000 flown miles.

The bottom line is that it’s best, if possible, to concentrate enough flying with one airline to earn elite status. General benefits of that include:

• always use first class checkin, always get to board early, also get priority seating and priority waitlists
• upgrades
• bonus miles, depending on the status level and airline, ranging from 25% to 125% on all your flown miles
• with some airlines, a better shot at redeeming miles for awards