Good catch Jonathan! It sure is a major hub for Southwest, but apparently not for Air Source, since it's been several months since anyone caught this. Unfortunately, when I downloaded the PDF's for each of the cities Southwest serves, I missed KHOU so I'll have to use alternative means to create the timetable out of Houston Hobby, since the PDF's are no longer available. In the meantime, if you need to fly out of Houston, you'll have to catch a taxi over to KIAH - George Bush Intercontinental and catch a flight out of there.