“He rode on a cherub and flew.” This is most likely a way of expressing that God rode on His cherubim-powered chariot-throne, as He did when He came to talk to Ezekiel in Ezekiel chapter 1. It is not likely that God rode piggyback style on a cherub.
[For more on God’s cherubim-powered chariot-throne, see commentary on Ezek. 1:26. For a more complete understanding of cherubim, see commentary on Ezek. 1:5 and Ezek. 1:10.]