If you add a crew member to the flight and he/she has no passport data added yet in his profile, you can do it now easily from a section SCHEDULE (tab CREW).
When a new poop-up window opens, fill it in with passport data (and other details if necessary) and save changes. If crew passport is valid, Leon will show a green dot in a tab PASSPORTS. If crew FTL calculations are up to the rules, a dot next to crew name will also turn green.
You can more than 1 passport for each crew, then in a section PASSPORTS mark the one which should be used for a particular flight.