> Fuel is the biggest single cost driver in commercial aviation, and aircraft use more fuel per unit distance

> the faster they go. This is why passenger jets are slower today than they were in 1965.

True, but this is misleading: the fuel economy of planes today are enormously improved over their 1960s progenitors and this is only in part because of reduced speeds. Computational fluid dynamics, improved engine design, superior material properties, etc. have resulted in significant improvements in aircraft design and efficiency. All of these factors have resulted in massively cheaper and safer travel (which lower costs through risk-adjustment).

> make supersonic aircraft for important government officials (cost being no object when tax dollars are used)

The unit cost of a new Gulfstream G650 is $64.5 million. Sounds as if cost is no object for more than just government officials.

>True, but this is misleading: the fuel economy of planes today are enormously improved over their 1960s progenitors and this is only in part because of reduced speeds.

It's not misleading at all. The reason planes are slower today is because it saves airlines money. The other stuff is true, but irrelevant. The reason we are not going to get supersonic commercial aviation, and the reason the Concorde failed, is that it's just too expensive.

One of the major reasons for Concorde failing was the sonic boom. As that boom restricted the routes it could travel on. Not the expense of fuel as their is market for fast and luxury travel.

That's why this move is so curious to me. All the major commercial carriers are effectively competing on ticket cost at this point, so the demand is for cheaper-per-passenger aircraft, not faster ones. It seems like in terms of pure economics the most feasible supersonic aircraft would be small business jets where speed and comfort are already prioritized and clients are willing to pay the premium.

Maybe this is somehow related to possible spaceplane advancements in the more distant future?

Cheap and fast is nicer than cheap and slow.

I recently booked a holiday in Thailand. Its a long haul to get there. I ended up changing my initial choice of part of Thailand to visit because I could fly direct for much the same price if I went to another region. All other choices involved a pit stop in Dubai.