> In travel, for example, you have the GDS companies (Sabre, Amadeus, etc.), ITA, and Expedia. Everybody else -- literally, everybody else -- layers on top of o

> In travel, for example, you have the GDS companies (Sabre, Amadeus, etc.), ITA, and Expedia. Everybody else -- literally, everybody else -- layers on top of one these systems. I thought Southwest was known for having their own system. Under the hood are they actually using a Sabre, Amadeus, etc.?