> 3. And air travel is just plain a bigger market these days than it was in the 1970s

It remains to be seen whether post-COVID wealthy travellers will subsidise BOOM development costs as opposed to not flying or continuing with smaller private jets as at present. Although Boom is “designing Overture to be the first post-pandemic airplane", they will need a massive investment to scale from the single-seat prototype (still to fly) to an operationally profitable vehicle.