It appears that United/Continental and American are working together to keep prices high in the Houston area.
American appears to have a lock on the Caribbean market, and United owns the Central and South American market. Southwest is trying to break in with International flights out of Houston, but needs Houston City Council's approval to expand Hobby Airport. United has been lobbying hard to stop Southwest and keep the Central and South American markets to themselves. Please look at and respond the the petition below!
Happyhorn
http://www.freehobbyairport.com/site/action-residents/