Errr ... how about no?

All my family lives in Europe. I live on the US west coast. "hopping city to city" would turn a 1 day nuissance into an arduous journey.

No thanks. I already see my family only once to twice a year.

Considering there are multiple flights per day between SFO and Paris and other EU hubs, I think my case is far from being a corner case.

NB the word "most". By your own admission, you make this journey once or twice a year.

And if it took any longer, I'd make this journey even less.

302,382 people flew from SFO to Europe in May 2016. That's a lot of people. Almost 5% of the Bay Area population and there are 2 more international airports in the region. [0]

[0] http://media.flysfo.com.s3.amazonaws.com/media/sfo/media/air...

Collectively far more people are flying from San Francisco to Los Angeles, San Diego, Phoenix, Las Vegas, Salt Lake City, Portland, and Seattle each month. If they could all show up at the airport 5 minutes early, hop in a tiny drone-jet with 3-4 other passengers and take off, not having to deal with security would be icing on the cake in terms of convenience.

I don't think the parent was suggesting that his idea should be the only solution... just that it would be a solution that would work for many use cases (and could exist in combination with larger long haul flights).

Another tactic that might help would be completely separating checked baggage from passenger flights. I.e. you check your bags the day before and they go on a cargo network. More time for screening, cargo planes are less valuable targets (although they still have been attacked), cargo containers could be armored, and passenger-only planes would be easier to secure since the only way to smuggle something would be on your person or in your body.

Even if you could theoretically reduce airport connection time to zero between flights, a lot of time is spent just getting the aircraft to speed, and slowing down to land (all that gravitational potential energy has to go somewhere, after all).

Same principle applies to express trains, and dwell times at stations. The benefit of high speed is lost just decelerating and accelerating from every stop it has to make.