The girls are in a spot: a gear has snapped clean in two, stopping the Kettenkrad, and their “last tour” in its tracks. If they can’t get it going, their chances of survival plummet. Chito can’t get it going, and Yuuri won’t help (probably aware there’s little she can do). She just cheerfully sings a little song with one lyric: “hopeless, hopeless.”
Then Yuuri spots an airplane flying in the sky, and Chito spots a woman in a white coat running after it. Hope has arrived, in the person of Ishii, who has taken up residence in an old underground aircraft hangar.
Ishii is a quietly kind yet no-nonsense person. She knows she can’t live in the base forever, so she’s using the plans she’s found to design and build an airplane to fly to the next city (the plane seen in they sky was a prototype).
More than a base, the hangar appears to be some kind of repository of aeronautical history, and just as Chito and Yuuri may be the last two people operating a Kettenkrad, Ishii is possibly the last aeronautical engineer and aviator left.
The girls help Ishii compete construction of her plane, and in exchange, she provides them with food, shelter, a bath (aaaaahhhh) and the part and repairs needed to get their ‘Krad going again, thus probably saving both their lives.
The day of the flight comes, and there’s a sense of finality and longing for the status quo that’s about to be blown to bits by the winds of progress. It won’t stay warm and calm for long; Ishii has to launch now. And she’s glad she has human witnesses for what could be the last manned flight.
After all, it’s only history if someone besides the one making it saw and documented the event. The takeoff sequence is appropriately epic in its portrayal, as is the awe in the girls’ eyes as they watch Ishii achieve flight.
For a few magnificent moments, the plane soars majestically over one of the widest and clearest views of the city we’ve yet seen; loaded with enough fuel to fly 2,000km, more than enough to reach the nearest city, just visible from Ishii’s giant telescope.
But a few moments is all the plane gets; it breaks up in midair, the pieces pathetically plummeting to the ground far, far below. Chito collapses in reaction, but Yuuri spots Ishii in a parachute, slowly descending. She’s okay, but she failed.
Still, Ishii feels a great sense of relief, to the fact she even smiles, which Yuuri interprets as her finally “embracing the hopelessness” all humans in this wrecked world must embrace in order to keep going. She falls and falls and falls, perhaps to the lowest level, but there’s every reason to believe she’ll survive.
As for Chito and Yuuri, they load up on as many ration potatoes they can find and set off in their repaired Kettenkrad, bound for still higher levels of the city. They, like Ishii and Kanazawa, are also a part of history…likely the tail end of it. When they, and whatever other scattering of remaining humans, have passed on, there will be nobody and nothing left but the ruins.
Or maybe, just maybe, there’s hope somewhere out there, waiting to be found. And maybe Yuuri wants to be proved wrong.