Well, luckily for Deku, he has a much better AP/Dura ratio than Aang, as well as much, MUCH better stamina. He loses in range and versatility, but wins in intelligence very badly.
Honestly I think Deku can take this. Aang's attacks aren't actually that much higher than Deku's durability, which isn't true vice versa. 2-3 hits from Deku and Aang is going to be KO'd fast, while Deku can take many hits from Aang and keep going. Aang's bending isn't actually hard to dodge either. Even with a severe terrain disadvantage, Deku can dodge or jump over most of Aang's attacks, and Air Bending barely even does damage to him, so he doesn't have to worry about being hit by it. Deku can also maneuver mid air quite well, even without something to bounce off of, so any non air bending attacks can be avoided.
Deku is far smarter than Aang too, so he'll easily be able to figure out how his bending works and use it to his advantage. He'll notice that Aang needs to be near water to control it, so he'll try to steer the fight away from it if he can. If Deku can get close to Aang, which he already is from starting positions, he can also restrain his hands and legs to prevent his bending, and since Deku has higher Lifting Strength too, Aang can't break free easily. He might be able to air bend out with his mouth, but all Deku has to do is hit him and he'll stop.
Aang's advantages are range, AP and versatility, while Deku has intelligence, lifting strength, durability and stamina. He should be able to take this after realizing what Aang's power is and getting in close. The fact that only water and earth bending even hurt Deku are a big boon since air bending is Aang's best counter to Deku getting close.
Deku might even be able to use Aang's earth bending against him by makikg it a platform to bounce off of, though that might be a stretch.
This fight is basically a glass cannon vs a sufficiently mobile, very smart tank. Deku has ways of getting close to Aang, can easily defeat him if he does, and only gets better at predicting and dodging Aang's attacks the more he sees his bending.
Definitely high difficulty, but Deku can win.