The youtube channel which originally leaked the airliner videos was called RegicideAnon and besides leaking multiple videos concerning the supposedly MH370 disappearance there was a last video uploaded: https://www.reddit.com/r/UFOs/comments/15nslal/ww2_archive_footage_of_flying_saucer/
Now whats interesting is that a voice changer has been used but the pronounciations do sound very similiar to David Grusch as another poster has noticed: https://www.reddit.com/r/UFOB/comments/15nvfia/this_guys_voice_has_the_same_exact_inflection_as
What makes me very curious is that a voice changer was used at all. Why the need to change your voice on some random UFO video on youtube.
If we assume David Grusch is the leaker of the airline videos this raises the following questions:
Could he have had access to satellite imagery or people who have access to it in that timespan of 2014? Did he, unsucessfully, try to leak the event before hand but decided to pursue more official ways after his unofficial approach failed to gain a significant amount of attention? Whats up with the archiving of the WW2 UFO Material, was that related to his work in the UAP-Taskforce?
This is just wild assumption based on the indicatives above.