After arriving in China, and before his first mission, Maj. Tom West was transferred from piloting a B-29 to Engineering Officer for the unit. He would be replacing the previous EO lost over the "Hump". General Wolfe said that he'd send West's crew back to Windover because, "an experienced crew was needed for a special mission". So even before its first mission this crew was being sent back to the States - because of its experience. Surly there were plenty of equally experienced crew members already state-side. This crew have been more valuable staying on as replacements/relief for sick/injured crew members of B-29s already in China.
At 1:04:42 there is a jet airliner possibly a Boeing 727, thirteen years before it entered service.