I havent known of any airline allowing anyone but staff or CAA into the flightdeck since 9/11.
Licence or not, you could be a terrorist.
After all the persons responsible for 9/11 had licences. If you were operating an aircraft, wether on the ground or in the air, would you let anyone you didnt know near the controls??
The deck of a big jet can be quite boring during flight anyway.
If you are that keen, buy a video, you can get them by a/c type and it is literallly the whole flight.