Custom Air questions

Planning a trip next spring on the Serenity repositioning through the canal. Would fly from Houston to San Juan, returning from San Diego to Houston. As platinums, we have free Custom Air as a perk but I am still not clear what it entails.

We are very concerned about wildly indirect connections from Houston to San Juan - like Newark!! for instance. With custom air, can we request the direct flights? Will there be a substantial upcharge for this?

We are usually able to use Continental points for the direct flights but have others with us on this trip and can't set up everyone with free air?

Thanks for your help. Without resolution of this we may take the Radiance out of Ft. Lauderdale instead but prefer a ship we haven't sailed - and it's newer.