Can't find anywere how long will be my self-created (in Flex Builder) certificate for AIR app valid? And how can I check exp. date?
The default is 5 years.
You can check in many ways. You can run keytool (java) to check it out by:
Keytool -list -storetype -keystore yourcert -storepass password ...
Look at the output for the validation period.
Retrieving data ...