YOU SAID:

there was a duck underneath a bridge, it was ducking from airplanes

INTO JAPANESE

橋の下にアヒルがいて、飛行機からアヒルを飛ばすのがやっていた

BACK INTO ENGLISH

There were ducks under the bridge and they were doing flying ducks from airplanes.

INTO JAPANESE

橋の下にはアヒルがいて、飛行機から飛んでくるアヒルをやっていました。

BACK INTO ENGLISH

There were ducks under the bridge, and they were doing ducks flying from planes.

INTO JAPANESE

橋の下にはアヒルがいて、飛行機から飛んでくるアヒルをやっていました。

BACK INTO ENGLISH

There were ducks under the bridge, and they were doing ducks flying from planes.