Just visit a flight tracking website before booking.
In addition I'm sure airlines not flying the MAX will be using that fact as a marketing tool (i.e. we only fly Airbus etc) so you could limit your bookings with just those airlines.
As an example of this, here in Australia I know one of the carriers is planning to fly the Max some time next year.
If they go ahead with that plan, I will be making sure not to book with that carrier at least for the next few years.
In addition I'm sure airlines not flying the MAX will be using that fact as a marketing tool (i.e. we only fly Airbus etc) so you could limit your bookings with just those airlines.
As an example of this, here in Australia I know one of the carriers is planning to fly the Max some time next year.
If they go ahead with that plan, I will be making sure not to book with that carrier at least for the next few years.