Abstract: The blade has its lower-surface and upper-surface skins of its shell, its front and rear filling bodies and its spar made of a composite material having the same thermoplastic matrix, preferably made of PEEK, reinforced preferably with carbon fibres. The spar is extended outside the shell by an integrated rooting part with linkage attachment, in a loop or laminate, in the same thermoplastic composite. The method consists in assembling, by melting, under pressure, all the thermoplastic composite components of the blade, in a single step after manufacturing these components in the form of prefabricated elementary pieces.