From reading his words, here is what it looks like to me:
-Point-to-point on routes with no competition. This means his price competition is with airlines that would need to operate 2 legs at least, which is obviously more expensive, so even at a 30% discount (in his words), they are still making a healthy profit. These routes are also going to be thin, thus the A220 being the answer metal-wise.
-Automated ticketing and customer service via the website and phone app, saving $$$. I'm guessing ancillary income to be a major part as well. Want to print your boarding pass at the airport? It's gonna cost you. Want to pick your seat? It's gonna cost you. Want to bring on a carry on? It's gonna cost you.
-Recruiting low hour pilots from regionals around the time they are upgrade eligible, giving them 121 experience, but being a stepping stone for the legacies. I expect pilot pay would represent a middle ground between regional and major as well, but the major benefit would be to get a type rating that will be in use at Delta (and perhaps others) in the near future.