This math is wrong. The MAX is a quarter of the all-737 fleet. If Alaska flew half Airbus, an a quarter of 737s were grounded, then it would a quarter of half, or an eighth. You're suggesting that the MAX would make up half their 737 fleet, "as time goes on", but then that would be true in an all 737 fleet as well. Either way you do it, the result of having some Airbus models would be a smaller portion of the fleet grounded.
