We did that ages ago:
And then the Daleks blew it up...
I know the Soviets flirted with the idea of a Submarine LST, long ago, and there was a brief period of aircraft being attached to submarines, even into the early jet age. But up until now aircraft have always been too big to fit into a submarine without making it bigger than a Typhoon with horrendous waterflow noise problems. Now we have UCAVs, well...I'd say that the chances were good before the century was out of a submarine with UCAV launching ability. It'd probably be like the Hurricanes we launched from merchant ships in WWII at first. Launch the UCAV, conduct the mission and then self-destruct it in the sea somewhere. But with hovering UCAVs will come VSTOL, and then the problem is solved.