Sobering but true: it's impossible to thoroughly test an IT system of any real size. Roger S. Pressman pointed out in his book Software Engineering, one of the classic texts in the field, that "exhaustive testing presents certain logistical problems....Even a small 100-line program with some nested paths and a single loop executing less than twenty times may require 10 to the power of 14 possible paths to be executed." To test all of those 100 trillion paths, he noted, assuming each could be evaluated in a millisecond, would take 3170 years.
First off, you can’t buy an AAirpass any longer. Not the pass as it was first envisioned anyway. American still does sell something called the AAirpass , but it’s a shell of the original product. The current pass is available only to customers who spend a minimum of $10,000 annually on American Airlines’ flights. The main benefit for pass holders is access to fixed rates that aren’t all that cheap, but that at least ensure travelers won’t get gouged as badly as the masses when booking flights at the last minute. For example, a flight from Chicago to Dallas costs a bit over $500 for a pass holder; the same trip, if booked on the day of travel by an average Joe, probably runs around $900. Today’s pass holders also get to check two bags free of charge, a perk that used to be standard for all travelers.