ɪn fˈaɪɾɚɹ ˈɛɹkɹæft ˈɛndʒɪnz, ɐn ɪmˈɜːdʒɪŋ kˈɑːnsɛpt ɪz ðə θɹˈiːstɹˈiːm ˈɑːɹkɪtˌɛktʃɚ, wˌɛɹ ɐ θˈɜːd bˈaɪpæs stɹˈiːm kæn biː jˈuːzd tʊ ɪŋkɹˈiːs bˈaɪpæs ɹˈeɪʃɪˌoʊ wɛn fjˈuːəl ɪfˈɪʃənsi ɪz ɹᵻkwˈaɪɚd, ɔːɹ hæv ɐdˈɪʃənəl ˈɛɹfloʊ dᵻɹˈɛktᵻd tə ðə kˈoːɹ fɔːɹ ɡɹˈeɪɾɚ pˈaʊɚ.
In fighter aircraft engines, an emerging concept is the three-stream architecture, where a third bypass stream can be used to increase bypass ratio when fuel efficiency is required, or have additional airflow directed to the core for greater power.