Note that Vasmer derives Old Church Slavonicперѫтъ(perǫtŭ, “they fly”) from Proto-Slavic*perti(“to fly”) (etymologically separate from the normal verb of that shape). This derivation is not consistent with evidence from other languages, which show that *perti has 1sg. *pьrǫ rather than **perǫ. Vasmer also includes Russianпере́ть(perétʹ, “to move, to travel”) as a derivative of this putative verb rather than as a colloquial, secondary development from the primary meaning "to drag".
Vasmer, Max (1964–1973) “пере́ть”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress
Formed as *perti + *-ati, descending either from Proto-Indo-European*per-(“to propel, forwards”) or from Proto-Indo-European*(s)perH-(“to trample, to spurn”) (see *perti for further explanation). The present tense declension continues the simple thematic forms *(s)per(H)-é-ti.
Vasmer, Max (1964–1973) “прать”, in Oleg Trubachyov, transl., Этимологический словарь русского языка [Etymological Dictionary of the Russian Language] (in Russian), Moscow: Progress
^ Derksen, Rick (2008) “*pьrati I”, in Etymological Dictionary of the Slavic Inherited Lexicon (Leiden Indo-European Etymological Dictionary Series; 4), Leiden, Boston: Brill, →ISBN, page 427: “v.”
^ Olander, Thomas (2001) “(po-)pьrati: -perǫ -peretь”, in Common Slavic Accentological Word List[1], Copenhagen: Editiones Olander: “c sparke, trykke (PR 139)”
^ Derksen, Rick (2008) “*pьrati II”, in Etymological Dictionary of the Slavic Inherited Lexicon (Leiden Indo-European Etymological Dictionary Series; 4), Leiden, Boston: Brill, →ISBN, page 427: “v. ‘beat, trample, wash’”
^ Olander, Thomas (2001) “pьrati: perǫ peretь”, in Common Slavic Accentological Word List[2], Copenhagen: Editiones Olander: “c vaske (SA 204, 236; PR 139)”
^ Snoj, Marko (2016) “práti”, in Slovenski etimološki slovar [Slovenian Etymology Dictionary] (in Slovene), 3rd edition, https://fran.si: “*pьra̋ti, sed. *pȅrǫ”
^ Kapović, Mate (2007) “The Development of Proto-Slavic Quantity”, in Wiener Slavistisches Jahrbuch[3], University of Vienna, page 6: “*pьra̋ti”