In his comment on YS IV 1, kRSNA-dvaipaayana sez, amongst other things: mantrairaakaashagamanaaNimaadilaabhaH
Attempt at s-v: mantraiH; aakaasha-gamana + aNimaa + aadi -laabhaH Possible translation: Yogic Flying (aakaasha-gamanam), aNimaa, etc (aadi) "are achieved" (laabhaH: acquisition, etc.) through mantras (mantraiH: instrumental plural). Vyaasa seems to compare YF with the eight mahaasiddhis (aNimaa, mahimaa, laghimaa, garimaa, etc.). Does he try to emphasize, that YF is best achieved through a mental technique, not e.g. praaNaayaama?