Almost all old warships of Federal were build on the ground. It was the way of the Federation from the same old era like the Launching ceremony. Those ships does not have an ability to re-entry to the atmosphere.
Zeon has developed a technology that enables space battleship flying in the atmosphere based on their own aviation mechanics. High-performance cruiser Zanzibar was able to Entry to the atmosphere, Return to space with the catapult and rocket booster.