IIRC, rumor has it the show was planning to introduce the Aeroshuttle in Season 4/5, even going so far as to create test footage and designs for the aeroshuttle. I believe the test footage looks similar to the runabout interiors because they were planning to reuse/redress the runabout sets for the aeroshuttle.
However, the idea was scrapped and the Delta Flyer was introduced in Season 5 instead. I'm fairly certain the reasoning behind this change was that TPTB didn't want to spend money on effects shots for the aeroshuttle AND new effects shots of Voyager sans aeroshuttle, rather than use existing stock footage to save some cheddar.
Of course, I could totally be remembering things wrong and just be pulling gagh out of my butt. I don't think I am though.
However, the idea was scrapped and the Delta Flyer was introduced in Season 5 instead. I'm fairly certain the reasoning behind this change was that TPTB didn't want to spend money on effects shots for the aeroshuttle AND new effects shots of Voyager sans aeroshuttle, rather than use existing stock footage to save some cheddar.
Of course, I could totally be remembering things wrong and just be pulling gagh out of my butt. I don't think I am though.