Delta and other airlines at the airport have specifically asked for Priority Lanes for their frequent fliers, but have been denied by the airport authority in Orlando countless times. I can only guess this is because they feel that it would have a negative affect on the overall general flying population due to Orlando's clientele (non-frequent flier leisure flyers) and thus back up lines even more.
As somebody mentioned, there is a TSA pre-check, which is essentially a Priority lane, assuming you are a gold medallion or up.