PSU Lion:
My previous corpopration, as well as my current one (for what it's worth) have similar deals with the airlines, for the same costing reasons as yours has. It adds up to a significant savings to the company over the year.
We are given reasonable latitude when booking our tickets, but if at all possible, the preferred airlines are...uh, well...preferred.
[This message has been edited by hnechets (edited 02-23-2000).]