And they will, at the second coming. As I have said before and demonstrated from Scripture a number of times, not every "cloud coming" in the Bible is the bodily second coming.
Just read Daniel 7. He goes up, not comes down. All with clouds.
Clouds in the Bible are like Gods royal raiment or His divine chariot. To be identified as "coming in clouds" is to be identified as God Almighty Himself. That is why the priests tore their robes in Matthew. 26. They understood exactly what He was saying when He said they would see Him coming in clouds. It was not atmospheric conditions that caught their attention, but the image of Gods throne from places like Daniel 7.
Yeh -- its one of those "not in the flesh" second comings that John warned us about [I John 4:2-3].