Hey long time no see
With what you are doing I can see a few possibilities of what might happen. One being that the laser ends up being ineffective because stevie gets used to it, another being that whilst he may not be phobic now, things can easily turn around. It may continue to work but I think the likeliest thing is he will just desensitize to it.
Now I don't know much about what else you have tried, how long you have tried them for etc but I think it is really important to find a more positive way of encouraging flight, whether the be through food management, bigger or better rewards or just giving him much more time to get used to his new flying status so he actually starts realising its fun and feels good to fly. Right now he has probably been a bit of a perch potato until recently and flying feels like so much effort even though he is capable of it.