Due to his amazing air maneuverability, Wario has many options after his d.air when he ends it early [by DI'ing away from the opponent before the move ends], such as throwing after landing. However, I've found that a really great mix-up that most people fall for is doing a Chomp before landing. Basically, just do a short hop d.air, then, right before the last hit of the d.air lands, DI away from the opponent and go into a Chomp. It works wonders as a surprise mix-up, especially against people who think they can just do "this and that" to get around Wario's air game. It's really funny to do it against people who try to shield-grab all of your aerials.
DI'ing out of the d.air was something that was covered in 56K's topic, but I just wanted to point this one out, as it's another option to do aside from double jumping after the d.air.
DI'ing out of the d.air was something that was covered in 56K's topic, but I just wanted to point this one out, as it's another option to do aside from double jumping after the d.air.