[chimpontherun]

This concept raises more questions than the site answers:

* what's the point of landing in tow? The safety aspects and the failure modes are enormous

* it's unclear where the 65% fuel saving comes from. Riding the wingtip vortex on the inside produces downward momentum. In order to generate positive lift from the wingtip vortex, the follower has to be outside of it (e.g., gaggles of geese in wedge formation)

* taking advantage of wake flows, while possible (although 65% is highly improbable), would always be less efficient than optimizing a single airframe so that it minimizes the wake generation in the first place

* the site is missing footage of real flights. The 3 clips 10-seconds long are not showing what they claim to be showing. Also, does the "see flight tests" link work for anybody?

[usrusr]

Taking an "optimist's advocate" position here (I share your scepticism):

65% are almost easy to achieve, with a bit of clever accounting: you'd look at fuel per ton-mile (that much is clear and perfectly fine) and then you just pick a tow plane that's maybe a bit overpowered but doesn't have much cargo capacity. If you look at fuel saving through that lense, the sky is the limit.

The contingency page in the pitch deck for when the "bigger plane is always more efficient" argument comes up would be looking at big end of the hypothetical size spectrum: when you want efficiency, a bigger plane means bigger wingspan. Air travel is in something not too dissimilar to the "panamax" situation on the oceans, everything on the ground stops at 747-sized (the A380 was carefully squeezed to mostly fit that profile). A formation can get a similar effect as a larger wingspan without exceeding runway dimensions.

(and as for landing in tow: perhaps some stupid legal angle, "it's all fully automated, but technically this is not autonomous because the lead aircraft pilot is in charge"?)

[regularfry]

The reverse - tow plane lands separately - has some interesting challenges. If the tow plane lands first and messes up the landing, blocking the runway, the lead plane now can't land. Fine if you've planned the fuel for a round trip, and fine if there's a currently-usable second runway, but I can see a huge draw for this in being able to get interesting cargo loads into and out of smaller airfields where that won't be available.

If the tow plane lands second then it needs to loiter, gliding autonomously, for as long as it takes for the lead plane to land and get out of the way. And that sounds like a much harder problem to do safely, particularly with the lead plane's pilot having to pay attention to landing and unable to control the tow plane if it gets into a dangerous state.