Revenge of the Fallen introduced us to one method transportation, Space Bridges, which is akin to a Wormhole if one is to think about it. Folding space and utilizing a Wormhole for instantaneous travel. But the primary method of space travel Autobots and Decepticons use does not involve Space Bridges. We merely see the Autobots, Decepticons, Starscream and Megatron leave and reach planets under their own power. The Alcubierre drive could explain Transformers primary method of space travel. Stretching space in a wave which would in theory cause the fabric of space ahead of a spacecraft to contract and the space behind it to expand. The ship would ride this wave inside a region known as a warp bubble of flat space. Since the ship is not moving within this bubble, but carried along as the region itself moves, conventional relativistic effects such as time dilation do not apply in the way they would in the case of a ship moving at high velocity through flat spacetime relative to other objects.