The two reasons most frequent travelers invest in a frequent flyer programs — status perks (e.g., free upgrades, pre-boarding) and free trips.  While comparing status perks between programs is pretty straight-forward — most airlines proudly list every status perk, the number of seats that can be booked with miles seems a closely guarded secret, making comparisons between frequent flyer programs difficult.

IdeaWorks, a travel consultancy led by ex-Midwest Airlines executives, took a shot at clearing away just a bit of the smoke by generating some real comparitive data on mileage seat availability.  Looking at the popular transatlantic awards, IdeaWorks “made 6,400 booking queries at the websites of five US-based airlines and five Europe-based airlines during the latter half of January 2009.”  That’s either some good web code or a lot of keyboard banging.

The results?  Iberia, the Spanish carrier, took top honors, offering reward seats for 83% of IdeaWork’s booking attempts.  American Airlines was the best US carrier at 58%, which earned it 4th place in the standings.  Indeed, the oneworld alliance took 3 of the top 4 spots.  The worst was no surprise — US Airways at a Scrooge-like 4% reward seat availability.  The full results are available here.