How did Superman get those trunks back after all?
According to The Man of Steel #6, it was out of necessity.
Spoilers ahead for The Man of Steel #6, out today.
As The Man of Steel wound down, the "fate" of Lois Lane and Jonathan Kent was finally revealed: Jon, wanting to explore the universe and learn more about his Kryptonian heritage, insisted to his parents that he was going to join Jor-El, his paternal grandfather, on an exploration of the cosmos. Superman objected, but Jon was insistent, and eventually Lois interceded to say that she, too, would leave and supervise their son's adventure in space.
“There's a big thing that happens in Man of Steel with Mr. Oz -- with Jor-El, and the entire House of El, Superman's family,” Bendis recently told ComicBook.com. “There is a shift I think people can see coming on some level, but I know for a fact that those who are fearing that these characters are going to go fly off into some other book or something and not be part of this is incorrect, but I can only prove that in the months ahead.”
Along the way, Superman gives Lois his costume -- apparently the one he had been wearing since the "Superman Reborn" story -- and tells her to wear it to protect herself, as it is made of impervious material.
Bendis thought out the technical stuff -- pushing a button on the inside of the belt buckle causes the clothing to conform to one's body -- and the practical.
"I'll find something," Clark promises Lois when she asks him what he will wear.
While the 2011 "New 52" reboot did away with Superman's trunks and they had not been seen regularly since until Action Comics #1000 this spring, the classic costume had popped up not too long ago: it, along with several other short-lived or variant Superman costumes including his "electric Superman" outfit, the black one he wore after coming back from the dead, and others, was on a rack in the Fortress of Solitude when Clark first brought Jon there early in Dan Jurgens's most recent run on the character.
It seems likely that Superman simply picked one of his old costumes off the rack -- the one he was most comfortable with, rather than the black one or another that would require more explanation -- and continued on his way.
The Man of Steel #6 is on sale today. Superman #1 and Action Comics #1,001 will both be on sale later this month.