We may also safely conclude that angels, God’s spirit messengers, travel at tremendous speeds. Thus once when Daniel began to pray, God dispatched an angel to him in answer to his prayer. This angel, although coming from beyond the realms of outer space, reached Daniel before he had concluded his prayer.—Dan. 9:21.
The Bible speaks of an invisible realm in which dwell spirit persons, the angels, much more powerful than man, who are able to travel through interstellar space where there is no atmosphere such as we on earth live in and, of course, they are beyond the need of any air such as we breathe and are not under its influence or control.
(yes speculation by the WTS was out there in the 60's and before)
Yes, in 1976, the WTS said is was no longer safe to conclude that.
However, there are some questions that are best left alone. Speculative inquiries merely “furnish questions for research rather than a dispensing of anything by God in connection with faith.” (1 Tim. 1:4) In building faith, what value is there in presenting elders or the Society with such problems as: How fast do angels travel, and how long does it take a spirit creature to travel from heaven to earth?
(I wonder what would happen if a jw would share that gem with another jw in their congregation?)