The fatality rates are 25 per 100 million occupant-miles traveled. That's far higher than for the Boeing 737 max.
Let's also compare their safety by time, instead of miles traveled.
Motorcycles: 25 / (100 x 10^6 / 60) = 0.000015 fatal crashes per hour
Boeing 737 max, assuming it averages 12 hour flight time per day, and using your 1/350 odds: 1/(350 x 365 x 12) = 0.00000065 fatal crashes per hour
The 737 max is still safer by an entire order of magnitude, even if you compared it by time spent traveling and not miles.
The fatality rates are 25 per 100 million occupant-miles traveled. That's far higher than for the Boeing 737 max.
Let's also compare their safety by time, instead of miles traveled.
Motorcycles: 25 / (100 x 10^6 / 60) = 0.000015 fatal crashes per hour
Boeing 737 max, assuming it averages 12 hour flight time per day, and using your 1/350 odds: 1/(350 x 365 x 12) = 0.00000065 fatal crashes per hour
The 737 max is still safer by an entire order of magnitude, even if you compared it by time spent traveling and not miles.