I'm sure we'll see it as a retrofit option. The road to autonomy as we know it involves robotic assistance for the meatbag first, followed by lots of supervised machine learning, and then a gradual phase out of meatbags who are sat there with a hand on the big red override switch. We'll see it with land vehicles first, then marine, then aviation.
Airlines know full well that they have to pay two very expensive pilots salaries when their effective professional utilisation is probably around the 3-5% mark. Most of the time they are staring at instruments of an aircraft that requires no intervention. Even if there is a mandate for human intervention, this could be done in the same way that military drone operations are done now - high reliability datalinks with a professional pilot at the other end, potentially controlling multiple aircraft if the required utilisation rate of the pilot is low. I'm not saying your passenger planes are going to be affected for decades yet, but semi-autonomous cargo? Probably could be done by 2025.