They could’ve emphasized that Han was using his smuggling skills to sneak the ground team onto the Endor moon. They could have even explained that Han himself paid for the clearance codes, using his criminal connections to procure them. And I do think having Han let Lando fly the Falcon also contributes to his character growth as well.
Yeah, and this suggests all sorts of enticing possibilities if only there was more time or more movies. I mean, you could have an entire subplot about Han and Lando going on a mission to get those clearance codes from like Black Sun or whatever, which could easily fill half a movie. And I think this highlights another issue with ROTJ: it was hampered from the start, because it had the monumental task of satisfactorily wrapping up the whole saga, which includes rescuing Han, resolving the conflict with Vader, revealing the “other”, and overthrowing the Empire, all in about 2 hours! And Empire Strikes Back didn’t exactly leave us off with the sense that some final showdown between the Empire and Rebellion was immanent. Considering all this, it’s really a miracle ROTJ turned out as good as it did.