An Etymological Dictionary of the German Language/fliegen
fliegen, vb., from the equiv. MidHG. vliegen, OHG. fliogan, ‘to fly’; comp. Du. vliegen, AS. fleógan (3rd sing. flŷhþ), E. to fly, OIc. fljúga; the common Teut. term for ‘to fly’; Goth. *fliugan may be inferred from the factitive flaugjan, ‘to keep on flying.’ Fliegen is in no wise connected with fliehen, as is proved by the initial sound of the root in Goth. þliuhan, ‘to flee,’ compared with usflaugjan; see Fliege, Vogel. Teut. root fliug, from pre-Teut. pleugh, plugh; akin to Lat. plûma for plûhma?. For an older root extending beyond Teut. see under Feder.