Moving from Flex to other technologies

Hi.. we have an application created using adobe flex. This application is really big with 300 pages written using MXML, AS3, and Java. We run this application on the browser flash player. Since flex is sunsetting, we need to think of other technologies... we need to minimize the migration effort and we are ok to run as a desktop client. Is moving to Air is the simplest way, if yes, is there any documentation or support available to do that?