[jsumrall]

No, its just not possible to maintain the integrity of the rocket if you're going to somehow lay it down on an inflatable. How could an inflatable withstand the temperature of the firing engines?

[gbhn]

For weight, the sides of a rocket are very thin. Think tin can. Vertical is OK but horizontal can't work.

[delecti]

Which makes sense. It's designed specifically to withstand a huge amount of vertical stress.