Bump for interest + accord. Other possibilities are: prefabs and/or robots/androids as an optional commodity, a number input box next to employ citizen, levels in construction increase rate, or deployable buildings. One thing I think should be kept in mind is that if platforms on hostile worlds won't support buildings until they themselves are finished, then there should be a method that doesn't require citizens. Alternatively, citizens should be able to work on these platforms in the same way that you don't have to worry about materials since they act as airports.
Edit: forgot a suggestion.
EDIT2: To avoid bumping the thread with a trivial point (MyBB really needs 'sage'). On thing I think should be emphasised is the lack of tech progression in construction after you reach the space age. Before that, every incremental improvement such as the hammer, electricity, SUVs and computers really made an impact and helped solidify the feeling of progress. Yet when you're building your first aerial platform, all that progress seems to have stopped, and things feel little different than trying to build a normal building without tools (try it when founding a colony, it's like night and day!). Something that acts as a space-age solution would therefore fall in line with this sentiment. Furthermore, the only solution I can think of that really scales with empire in the space age is your spacecraft manufacturing capability, and therefore the solution I would most strongly support is the constructor bay.
Edit: forgot a suggestion.
EDIT2: To avoid bumping the thread with a trivial point (MyBB really needs 'sage'). On thing I think should be emphasised is the lack of tech progression in construction after you reach the space age. Before that, every incremental improvement such as the hammer, electricity, SUVs and computers really made an impact and helped solidify the feeling of progress. Yet when you're building your first aerial platform, all that progress seems to have stopped, and things feel little different than trying to build a normal building without tools (try it when founding a colony, it's like night and day!). Something that acts as a space-age solution would therefore fall in line with this sentiment. Furthermore, the only solution I can think of that really scales with empire in the space age is your spacecraft manufacturing capability, and therefore the solution I would most strongly support is the constructor bay.